Substituted tyrosyl diamide compounds

ABSTRACT

The present invention provides substituted tyrosyl diamide compounds of general Formula I: ##STR1## and the pharmaceutically-acceptable salts thereof, which are useful for inducing analgesia in animals, pharmaceutical compositions comprising a pharmaceutically-acceptable carrier and a compound of Formula I, and a method for inducing analgesia in an animal in need thereof comprising administering a therapeutically-effective amount of a compound of Formula I to the animal.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present invention provides novel compounds having pharmaceuticalactivity which are useful as pharmaceutical agents and, moreparticularly, as analgesic agents for the treatment of pain in animals,pharmaceutical compositions containing one or more of these compounds,methods of use employing these compounds and methods of manufacturingthese compounds.

More specifically, the present invention concerns: (1) substitutedtyrosyl diamide compounds which, by apparently acting asneurotransmitters or neuromodulators in the central nervouspain-suppressant system, induce analgesia in animals; (2) pharmaceuticalcompositions containing one or more of these compounds in combinationwith a pharmaceutically-acceptable carrier; and (3) methods of treatingpain employing these compounds.

Analgesic compounds are agents which alleviate pain without causing aloss of consciousness and, thus, which are useful for treating pain and,often, for reducing inflammation.

The major classes of analgesic compounds include analgesic-antipyreticcompounds, which are compounds which alleviate pain and/or reduce fever,such as salicylates, and narcotic analgesics, or opiates, compoundswhich alleviate pain and/or induce sleep.

While salicylate and salicylate-like agents (non-steroidalantiinflammatory agents or NSAIDS) are efficacious in relieving pain,they often exhibit undesirable side effects, such as gastrointestinalirritation, including bleeding, as with aspirin, allergic response, aswith aspirin, and/or liver toxicity with extended use, as withacetaminophen.

The compounds of the present invention are not salicylates, andrepresent another class of compounds which are useful as analgesicagents.

(2) Description of the Related Art

Opioids are a class of drugs which are, to varying degrees, opium-likeor morphine-like in their properties. Although opioids are employedtherapeutically primarily as analgesics they have many otherpharmacological effects as well, and they have some of the properties ofcertain naturally-occurring peptides.

By the year 1967, researchers working in the art had concluded that thecomplex interactions in the body between morphine agonists(morphine-like drugs) and mixed morphine agonist-antagonists could bestbe explained by postulating the existence of more than one type ofcellular receptor for the opioids, and for related drugs.

Subsequent research in the area revealed that multiple categories ofopioid receptors exist and, further, that there ar at least threedistinct families of naturally-occurring opioid peptides: (1) theendorphins; (2) the enkephalins; and (3) the dynorphins.

Although studies concerning the binding of opioid drugs and peptides tospecific sites in the brain, and in other organs, have suggested theexistence of, perhaps, as many as eight different types of opioidreceptors in the body, there is reasonably firm evidence to support theconclusion that three major categories of opioid receptors, designatedμ, κ and δ, exist in the central nervous system. The classical opioidantagonist, naloxone, has been found to bind with high affinity to allthree categories of opioid receptors.

The multiplicity of opioid receptor types in the central nervous systemis now well established. Though much work has been directed at definingthe structural elements that determine receptor specificity andefficacy, these factors are still, at best, poorly understood.

The rigid alkaloid opiates, typified by morphine, are generally believedto produce analgesia by interacting with the μ receptor.

It is now well established that the δ opioid receptor type mediatesanalgesia in the mouse, and that this site is generally associated withfewer gastrointestinal transit effects, and with less physicaldependence, than the μ opioid receptor type.

In 1975, Hughes and Kosterlitz described the isolation of twonaturally-occurring pentapeptides, "methionine enkephalin" (H₂N-Tyr-Gly-Gly-Phe-Met-OH) and "leucine enkephalin" (H₂N-Tyr-Gly-Gly-Phe-Leu-OH), from the brain. These pentapeptides occur innerve endings of brain tissue, spinal cord and the gastrointestinaltract, bind to the same receptor sites as do the opiates, and exhibitsome weak morphine-like actions, actions which were antagonized bynaloxone.

That same year, Goldstein and his colleagues reported the presence ofpeptide-like substances in the pituitary gland which exhibited opioidactivity.

The naturally-occurring pentapeptides isolated by Hughes and Kosterlitzappear to act as neurotransmitters or neuromodulators in the centralnervous system, and bind stereospecifically to partially-purified brainopioid receptor sites. See, for example, Bradbury et al., Nature, 260,793 (1976). These natural peptides are also highly active in bioassaysfor opioid activity, but exhibit only weak, fleeting analgesic activitywhen injected directly into the brain of the rat, and exhibit noactivity when administered systemically in the rodent. See, for example,Belluzzi, et al., Nature, 260, 625 (1976).

In an attempt to overcome the lack of in vivo activity of thenaturally-occurring pentapeptides isolated by Hughes and Kosterlitz,investigators working in the art have made numerous modifications tothese enkephalins.

Among the modifications made to methionine enkephalin has been thesynthesis of short-chain, enkephalin-like peptides, among them dipeptideand tripeptide alkylamides, as described by Kiso et al., "PeptideChemistry 1981," Protein Research Foundation, Osaka, Japan, 65-70(1982).

Vavrek et al., Peptides, 2, 303 (1981), disclose analogs of theenkephalins, including the dipeptide,tyrosine-D-alanine-phenylpropylamide.

The large-scale use of synthetic enkephalins has been impractical due tovarious difficulties. One of the difficulties associated with naturalenkephalins is that they are extremely unstable, and their half-lives inthe blood are extremely short.

Attempts at solving these problems have focused upon altering thestructure of the enkephalin molecule. Alterations in the enkephalinstructure produce different pharmacological effects. To some degree,these effects are due to differential interactions with the variousopioid receptors. However, it has been difficult to study the role ofeach receptor type, or to induce selectively the pharmacological andtherapeutic effects associated with each receptor type, because theenkephalin analogs, to date, have had a high degree of selectivity foronly the mu (μ), ralher than for the delta (δ), opioid receptors.

For several years, the prototypic agonist for the δ opioid receptor hasbeen the cyclic enkephalin analog [D-Pen², D-Pen⁵ ]enkephalin. Therecently-discovered deltorphins, heptapeptides of frog skin origin, arealso highly selective and potent, in vitro, at this receptor. However,the relatively large size of these peptides suggest potential problemsin crossing the blood brain barrier to elicit analgesia after systemicadministration, a desirable property for a useful opioid analgesic. Thishas also hampered attempts to more fully define the functional role of δreceptors in the central nervous system.

Compounds within the present invention are tyrosyl diamide opioidagonists which have a substantial affinity for both the μ and the δopioid receptors, and which produce analgesia following central andperipheral routes of administration in animals.

The compounds of the present invention are structurally distinct fromthat which has been described in the art.

Moreover, compounds of the present invention exhibit unexpected andsurprisingly superior analgesic activity when compared to compounds ofthe prior art. These novel tyrosyl diamide compounds show improvedpotency and bioavailability as analgesic agents by central andperipheral routes of administration, such as by subcutaneousadministration.

A. R. Jacobson et al., in "Minimum-Structure Enkephalin AnaloguesIncorporating L-Tyrosine, D (or L)-Phenylalanine, and a Diamine Spacer,"J. Med. Chem., 32, 1708-1717 (1989), disclose a series of compounds inwhich L-tyrosine was linked to N-acyl phenylalanine through a variety ofdiamine spacers. Tyrosyl diamide compounds within the present inventionwere found to be surprisingly and unexpectedly superior to the peptidecompounds described by Jacobson et al., as will be discussed in moredetail hereinbelow.

SUMMARY OF THE INVENTION

The present invention provides compounds having a structure of FormulaI: ##STR2## and the pharmaceutically-acceptable salts thereof, wherein:R¹ is hydrogen, alkyl having from 1 to 4 carbon atoms or acetyl;

R², R³, R⁴, R⁵, R⁶, R¹⁴ and R¹⁵ may each be the same or different, andare each independently hydrogen or alkyl having from 1 to 4 carbonatoms;

R⁷ is hydrogen or t-butyloxycarbonyl;

R⁸ is hydrogen, alkyl having from 1 to 4 carbon atoms or may be takentogether with R⁹, R¹⁰, --(CH_(i))_(m) --, R¹¹, R¹² and R¹³ to form asingle-ring, nonaromatic structure;

R⁹ is hydrogen, alkyl having from 1 to 4 carbon atoms or may be takentogether with R⁵, R¹⁰, --(CH_(i))_(m) --, R¹¹, R¹² and R¹³ to form asingle-ring, nonaromatic structure, or

may be taken together with R¹⁰, --(CH_(i))_(m) --, R¹¹, R¹² and R¹³ toform a single-ring, nonaromatic structure, or

may be taken together with R¹⁰, --(CH_(i))_(m) --, R¹¹ and R¹² to form asingle-ring, aromatic structure;

R¹⁰ is hydrogen, alkyl having from 1 to 4 carbon atoms or may be takentogether with R⁵, R⁹, --(CH_(i))_(m) --, R¹¹, R¹² and R¹³ to form asingle-ring, nonaromatic structure, or

may be taken together with R⁹, --(CH_(i))_(m) --, R¹¹, R¹² and R¹³ toform a single-ring, nonaromatic structure, or

may be taken together with R⁹, --(CH_(i))_(m) --, R¹¹ and R¹² to form asingle-ring, aromatic structure;

R¹¹ is hydrogen, alkyl having from 1 to 4 carbon atoms or may be takentogether with R⁵, R⁹, R¹⁰, --(CH_(i))_(m) --, R¹² and R¹³ to form asingle-ring, nonaromatic structure, or

may be taken together with R⁹, R¹⁰, --(CH_(i))_(m) --, R¹² and R¹³ toform a single-ring, nonaromatic structure, or

may be taken together with R⁹, R¹⁰, --(CH_(i))_(m) --, and R¹² to form asingle-ring, aromatic structure;

R¹² is hydrogen, alkyl having 1 to 4 carbon atoms or may be takentogether with R⁵, R⁹, R¹⁰, --(CH_(i))_(m) --, R¹¹ and R¹³ to form asingle-ring, nonaromatic structure, or

may be taken together with R⁹, R¹⁰, --(CH_(i))_(m) --, R¹¹ and R¹³ toform a single-ring, nonaromatic structure, or

may be taken together with R⁹, R¹⁰, --(CH_(i))_(m) -- and R¹¹ to form asingle-ring, aromatic structure;

R¹³ is hydrogen, alkyl having 1 to 4 carbon atoms or may be takentogether with R⁵, R⁹, R¹⁰, --(CH_(i))_(m), R¹¹ and R¹² to form asingle-ring, nonaromatic structure, or

may be taken together with R⁹, R¹⁰, --(CH_(i))_(m) --, R¹¹ and R¹² toform a single-ring, nonaromatic structure;

R¹⁶ is hydrogen, acetyl, ##STR3## W is --CH₂ --, oxygen or --NH--; R¹⁷is alkyl, alkaryl, alkenyl, alkylcarboalkoxy or sulfonylaryl;

X is hydrogen, halogen or alkyl having from 1 to 4 carbon atoms;

Y is hydrogen or alkyl having from 1 to 4 carbon atoms;

i is an integer of from 0 to 2;

m is an integer of from 0 to 6; and

n is an integer of from 0 to 6,

with the proviso that R², R³, R⁴ and R⁵ cannot each be hydrogen when:

(1) m is 0 or 1; and

(2) n is 1; and

(3) R¹⁶ is acetyl; and

(4) i is 2; and

(5) R¹, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹, R¹², R¹³, R¹⁴, R¹⁵,

X and Y are each hydrogen; or

R⁹ and R¹⁰ are each methyl; or

R¹¹ and R¹² are each methyl.

The present invention also provides pharmaceutical compositions whichare pharmaceutically acceptable, and which comprise atherapeutically-effective amount of a compound of Formula I incombination with a pharmaceutically-acceptable carrier, and a method foreliminating or ameliorating pain in an animal comprising administering atherapeutically-effective amount of a compound of Formula I to theanimal.

DETAILED DESCRIPTION OF THE INVENTION (1) Definitions

For purposes of clarity, the terms and phrases used throughout thisspecification and the appended claims are defined in the manner setforth directly below.

Some of the chemical structures which are presented in thisspecification and the appended claims have been drawn using theconvention which employs lines to represent alkyl radicals, which isknown by those of skill in the art.

The symbols " " and " " as used herein denote one of two possiblestereoisomers.

The abbreviation "Ac" and the term "acetyl" as used herein mean thegroup ##STR4##

The abbreviation "acyl" as used herein means ##STR5##

The abbreviations "AcOH" and "HOAc" as used herein mean ##STR6## andacetic acid.

The term "alkyl" as used herein means a saturated hydrocarbon radicalhaving from one to ten carbon atoms, within which includes from one tofive carbon atoms, and further within which includes from one to threecarbon atoms, which can be a straight or branched chain. Representativeof such radicals are methyl, ethyl, n-propyl, isopropyl, n-butyl,sec-butyl, isobutyl, tert-butyl, 2-ethylhexyl and the like.

The term "alkylamino" as used herein means an alkyl radical, as definedabove, having an amino group as defined below, attached thereto.

The term "alkylaminocarbonyl" as used herein means an alkylaminoradical, as defined above, having a carbonyl group, as defined below,attached thereto.

The term "alkylcarbonyl" as used herein means an alkyl radical, asdefined above, having a carbonyl group, as defined below, attachedthereto.

The term "alkaryl" as used herein means an alkyl radical, as definedabove, having one or more hydrogen atoms replaced by an aryl radical, asdefined below.

The term "alkenyl" as used herein means a hydrocarbon radical havingfrom one to ten carbon atoms, within which includes from one to fivecarbon atoms, and further within which includes from one to three carbonatoms, which can be a straight or branched chain, and which containsfrom one to two --CH═CH-- groups.

The term "alkoxy" as used herein means an alkyl radical, as definedabove, having an oxygen atom attached thereto. Representative alkoxygroups include methoxy, ethoxy, n-propoxy, tert-butoxy and the like.

The term "alkoxyaryl" as used herein means an alkoxy radical, as definedabove, including an aryl radical, as defined below.

The term "alkoxycarbonyl" as used herein means an alkoxy radical, asdefined above, including a carbonyl group, as defined below.

The term "alkylcarboalkoxy" as used herein means an alkylcarbonyl group,as defined above, which is attached to an alkoxy group, as definedabove, through a ##STR7## bond.

The term "alkynyl" as used herein means a hydrocarbon radical havingfrom one to ten carbon atoms, within which includes from one to fivecarbon atoms, and further within which includes from one to three carbonatoms, which can be a straight or branched chain, and which containsfrom one to two --C═C-- groups.

The term "alkynylaryl" as used herein means an alkynyl group, as definedabove, including an aryl group, as defined below.

The term "amino" as used herein means --NH₂.

The term "aminoacetyl" as used herein means ##STR8##

The term "aminocarbonyl" as used herein means ##STR9##

The term "analgesia" as used herein means the reduction, or absence, ofsensibility to pain, designating particularly the relief of pain withoutloss of consciousness.

The term "animal" as used herein includes mammals and non-mammals, andfurther includes humans and non-human mammals.

The term "aryl" and the abbreviation "Ar" as used herein meanunsubstituted, mono- and/or di-substituted 5-and 6-membered single-ringaromatic radicals, for example, phenyl. In Formula I, and in the GeneralReaction Schemes contained herein, the term "aryl" and the abbreviation"Ar" in conjunction with the variables X and Y mean mono-ordi-substituted 5- and 6-membered single-ring aromatic radicals.

The term "aralkyl" as used herein means an aryl radical, as definedabove, having one or more hydrogen atoms replaced by an alkyl radical,as defined above, for example, N-methylpyrrolyl.

The abbreviation "Bzl" and the term "benzyl" as used herein means C₆ H₅CH₂ --.

The phrase "blood brain barrier" as used herein means a chemical barriermade up by the cell walls of the capillaries which are present in thebrain tissues, through which drugs circulating in the blood must pass inorder to have an effect in the central nervous system.

The abbreviation "Boc" as used herein means t-butyloxycarbonyl.

The abbreviation "Boc-D-Ala" as used herein meanst-butyloxycarbonyl-D-alanine.

The phrase "Boc-DMT" as used herein means Boc-2,6-L-dimethyltyrosine.

The abbreviation "C" as used herein means the C or carboxy terminus ofan amino acid or peptide or the element carbon, depending upon thecontext in which it is used, as is known by those of skill in the art.

The term "carbonyl" as used herein means ##STR10##

The term "carboxyl" as used herein means ##STR11##

The abbreviation "CH₂ Cl₂ " as used herein means methylene chloride.

The term "composition" as used herein means a product which results fromthe combining of more than one element or ingredient.

The term "dialkylaminocarbonyl" as used herein means ##STR12## wherein Wand Z are each independently alkyl, as defined above.

The term "dialkylamino" as used herein means ##STR13## wherein W and Zare each independently alkyl, as defined above.

The abbreviation "DCC" as used herein means dicyclohexy carbodiimide.

The abbreviation "DIEA" as used herein means diisopropylethylamine.

The abbreviation "DMF" as used herein means dimethylformamide.

The phrase "ED₅₀ value" as used herein means that dose of a compound ordrug which produced a biological effect, such as producing analgesia, in50% of the animals to which the compound or drug was administered.

The abbreviation "Et" as used herein means ethyl (--CH₂ CH₃).

The abbreviation "Et₂ O" as used herein means diethyl ether.

The term "Et₃ N" as used herein means triethylamine.

The abbreviation "EtOAc" as used herein means ethyl acetate.

The abbreviation "EtOH" as used herein means ethanol (CH₃ CH₂ OH).

The term "halo" or "halogen" as used herein means chlorine (Cl), bromine(Br), fluorine (F) and/or iodine (I).

The term "heteroatom" as used herein means an atom of any element otherthan carbon or hydrogen.

The abbreviation "HOBT" as used herein means 1-hydroxybenzotriazole.

The term "hydroxy" as used herein means -OH.

The abbreviation "IBCF" as used herein means isobutylchloroformate.

The abbreviation "i.g." as used herein means that a compound or drug wasadministered intragastrically.

The abbreviation "Me" as used herein means methyl (--CH₃).

The abbreviation "MeOH" as used herein means methanol (CH₃ OH).

The abbreviation "N" as used herein means the N or amino terminus of anamino acid or peptide and/or the element nitrogen, depending upon thecontext in which it is used, as is known by those of skill in the art.

The abbreviation "N-Ac-Phe" as used herein means N-acetyl-phenylalanine.

The acronym "NSAID" as used herein means nonsteroidal antiinflammatorydrug, as discussed by J. G. Lombardino, Ed. NonsteroidalAntiinflammatory Drugs, Chemistry and Pharmacology of Drug Series,Wiley, New York (1985).

The term "nitro" as used herein means --NO₂.

The phrases "parenteral administration" and "administered parenterally"as used herein means modes of administration other than enteral andtopical administration, usually by injection, and includes, withoutlimitation, intravenous, intramuscular, intraarterial, intrathecal,intracapsular, intraorbital, intracardiac, intradermal, intraperitoneal,transtracheal, subcutaneous, subcuticular, intraarticulare, subcapsular,subarachnoid, intraspinal and intrasternal injection and infusion.

The abbreviation "NMM" as used herein means N-methylmorpholine.

The phrase "pharmaceutically acceptable" is employed herein to refer tothose compounds, materials, compositions, and/or dosage forms which are,within the scope of sound medical judgment, suitable for use in contactwith the tissues of human beings and animals without excessive toxicity,irritation, allergic response, or other problem or complication,commensurate with a reasonable benefit/risk ratio.

The phrase "pharmaceutically-acceptable carrier" as used herein means apharmaceutically-acceptable material, composition or vehicle, as defineddirectly above, such as a liquid or solid filler, diluent, excipient,solvent or encapsulating material, involved in carrying or transportinga chemical compound or pharmaceutical agent from one organ, or portionof the body, to another organ, or portion of the body. Some examples ofmaterials which can serve as pharmaceutically-acceptable carriersinclude: (I) sugars, such as lactose, glucose and sucrose; (2) starches,such as corn starch and potato starch; (3) cellulose, and itsderivatives, such as sodium carboxymethyl cellulose, ethyl cellulose andcellulose acetate; (4) powdered tragacanth; (5) malt; (6) gelatin; (7)talc; (8) excipients, such as cocoa butter and suppository waxes; (9)oils, such as peanut oil, cottonseed oil, safflower oil, sesame oil,olive oil, corn oil and soybean oil; (10) glycols, such as propyleneglycol; (11) polyols, such as glycerin, sorbitol mannitol andpolyethylene glycol; (12) esters, such as ethyl oleate and ethyllaurate; (13) agar; (14) buffering agents, such as magnesium hydroxideand aluminum hydroxide; (15) alginic acid; (16) pyrogen-free water; (17)isotonic saline; (18) Ringer's solution; (19) ethyl alcohol; (20)phosphate buffer solutions; and (21) other non-toxic compatiblesubstances employed in pharmaceutical formulations.

The phrase "pharmaceutically-acceptable salts" as used herein refers tonon-toxic salts of the compounds of the present invention which aregenerally prepared by reacting the free base with a suitable organic orinorganic acid, or which are prepared by reacting the free acid with asuitable base. Representative salts include the hydrochloride,hydrobromide, sulfate, bisulfate, acetate, oxalate, valerate, oleate,palmitate, stearate, laurate, borate, benzoate, lactate, phosphate,tosylate, citrate, maleate, fumarate, succinate, tartrate, napsylate,clavulanate and the like salts and alkali metal salts, such as sodiumand potassium, and alkaline earth salts, such as calcium and magnesium.

The abbreviation "Ph" and the term "phenyl" as used herein means thegroup C₆ H₅ --, derived from benzene.

The abbreviation "p.o." as used herein means that a compound or drug wasadministered orally.

The phrase "protecting group" as used herein means substituents whichprotect the reactive functional group from undesirable chemicalreactions. Examples of such protecting groups include esters ofcarboxylic acids, ethers of alcohols and acetals and ketals of aldehydesand ketones.

The phrase "N-protecting group" or "N-protected" as used herein meansthose groups intended to protect the N-terminus of an amino acid orpeptide, to protect an amino group against undesirable reactions duringsynthetic procedures and includes, but is not limited to, sulfonyl,acyl, acetyl, pivaloyl, t-butyloxycarbonyl (Boc), benzyloxycarbonyl(Cbz), benzoyl and an L- or D-aminoacyl residue, which may itself beN-protected similarly.

The abbreviation "RaNi" as used herein means Raney nickel.

The abbreviation "s.c." as used herein means that a compound or drug wasadministered subcutaneously.

The term "sulfonylaryl" as used herein means ##STR14## wherein Ar is asdefined above.

The phrases "systemic administration" and "peripheral administration" asused herein mean the administration of a compound, drug or othermaterial other than directly into the central nervous system, such thatit enters the patient's system and, thus, is subject to metabolism andother like processes, for example, subcutaneous administration.

The abbreviation "TEAP" as used herein means triethylamine-phosphatebuffer.

The abbreviation "TFA" as used herein means trifluoroacetic acid.

The phrase "therapeutically-effective amount" as used herein means thatamount of a compound, material, or composition which is effective foreliminating or ameliorating pain in an animal, or for producing someother desired therapeutic effect, at a reasonable benefit/risk ratioapplicable to any medical treatment.

The abbreviation "THF" as used herein means tetrahydrofuran.

The phrases "title compound," "title product," "title peptide" and"title material" as used herein mean that compound, product, peptide ormaterial whose chemical name is given, and whose structure is shown, inthe particular example, or subpart thereof, referred to. If noparticular example, or subpart thereof, is referred to, it means thatcompound, product, peptide or material whose chemical name is given, andwhose structure is shown, in the particular example, or subpart thereof,in which it appears.

The term "trifluoroacetyl" as used herein means CF₃ CH₂ CO--.

The phase "Z group" as used herein means benzyloxycarbonyl group.

The abbreviation "Z-Phe" as used herein meansN-benzyloxycarbonyl-L-phenylalanine.

Amino acids appearing herein may be identified according to thefollowing three-letter abbreviations.

    ______________________________________                                                       Three-Letter                                                   Amino Acid     Abbreviation                                                   ______________________________________                                        Alanine        Ala                                                            Arginine       Arg                                                            Asparagine     Asn                                                            Aspartic Acid  Asp                                                            Cysteine       Cys                                                            Glutamine      Gln                                                            Glutamic Acid  Glu                                                            Histidine      His                                                            Isoleucine     Ile                                                            Leucine        Leu                                                            Lysine         Lys                                                            Methionine     Met                                                            Penicillamine  Pen                                                            Phenylalanine  Phe                                                            Proline        Pro                                                            Serine         Ser                                                            Threonine      Thr                                                            Tryptophan     Trp                                                            Tyrosine       Tyr                                                            Valine         Val                                                            ______________________________________                                    

The letters "L" and "D" appearing herein indicate whether a particularamino acid has the naturally-occurring configuration (L) or has thenonnaturally occurring configuration (D). Unless otherwise indicated,such as in the names or the structures for the various compoundsappearing herein, the amino acids appearing herein are L-enantiomorphs,rather than D-enantiomorphs.

(2) Description of Invention

In one aspect, the present invention provides compounds comprising astructure of Formula I, as described above in the "Summary of Invention"section, which are pharmaceutically acceptable, andpharmaceutically-acceptable salts thereof.

The compounds of the present invention comprise a class of substitutedtyrosyl diamide compounds which contain: (1) a tyrosine, or modifiedtyrosine, amino acid residue; (2) a diamine spacer unit located betweena tyrosine, or modified tyrosine, amino acid residue and aphenylalanine, or modified phenylalanine, amino acid residue, whichjoins the two amino acid residues together through an amide linkage; and(3) a phenylalanine, or modified phenylalanine, amino acid residue.

Although the compounds of the present invention contain two amino acidresidues, they are not dipeptide compounds, because they arestructurally different from true dipeptide compounds. While a truedipeptide compound has the amino-terminus of the second amino acidresidue in the sequence joined by a peptide linkage to thecarboxy-terminus of the first amino acid residue in the sequence, thetyrosyl diamide compounds of the present invention have thecarboxy-terminus of the second amino acid residue in the sequence joinedto a diamine spacer arm, with the diamine spacer arm being joined to thecarboxy-terminus of the first amino acid residue in the sequence. Thus,as is illustrated directly below, the second amino acid residue in thesequence is inverted, so that the left end of the residue is the carboxyterminus of the amino acid, and the right end of the residue is theamino-terminus of the amino acid. ##STR15##

The diamine spacer arm which links the two amino acid residues togethercontains two --NH groups, which may be connected directly together toform an --NH--NH-- group, or which may include straight- orbranched-chain alkyl radicals between the two nitrogen atoms, preferablyhaving from 1 to 4 carbon atoms. For example, the compound described inExample 47 has the following diamine spacer arm: ##STR16##

Preferably, the diamine spacer arm contains the two nitrogen atomsseparated by a --CH₂ --CH₂ -- group.

Preferred compounds of the present invention are those in which the R⁹and R¹⁰ positions thereof, as shown in Formula I, are each methyl. Themost preferred compound of the present invention is the compound shownand described in Example 47.

Specific compounds contemplated as falling within the scope of theinvention include, but are not limited to, the compounds discussed inthe examples presented below, as well as theirpharmaceutically-acceptable salts.

Contemplated equivalents of the compounds described in Formula I includecompounds which otherwise correspond thereto, and which have the samegeneral properties thereof, wherein one or more simple variations ofsubstituents are made which do not adversely affect the efficacy of thecompound.

Certain compounds of this invention may exist in geometric orstereoisomeric forms. The present invention contemplates all suchcompounds, including cis- and trans-geometric isomers, R- andS-enantiomers, diastereomers, d-isomers, 1-isomers, the racemic mixturesthereof, and other mixtures thereof, as falling within the scope of theinvention. Additional asymmetric carbon atoms may be present in asubstituent such as an alkyl group. All such isomers, as well asmixtures thereof, are intended to be included in this invention.

Certain compounds of the present invention may contain a basicfunctional group, such as amino or alkylamino, and are, thus, capable offorming pharmaceutically-acceptable salts withpharmaceutically-acceptable acids. The term "pharmaceutically-acceptablesalts" in this respect, refers to the relatively non-toxic, inorganicand organic acid addition salts of compounds of the present invention.These salts can be prepared in situ during the final isolation andpurification of the compounds of the invention, or by separatelyreacting a purified compound of the invention in its free base form witha suitable organic or inorganic acid, and isolating the salt thusformed. Representative salts include the hydrobromide, hydrochloride,sulfate, bisulfate, phosphate, nitrate, acetate, valerate, oleate,palmitate, stearate, laurate, benzoate, lactate, phosphate, tosylate,citrate, maleate, fumarate, succinate, tartrate, napthylate, mesylate,glucoheptonate, lactobionate, and laurylsulphonate salts and the like.(See, for example, S. M. Berge et al., "Pharmaceutical Salts," J. Pharm.Sci., 66:1-19 (1977).)

In other cases, the compounds of the invention may contain one or moreacidic functional groups and, thus, are capable of formingpharmaceutically-acceptable salts with pharmaceutically-acceptablebases. The term "pharmaceutically-acceptable salts" in these instancesrefers to the relatively non-toxic, inorganic and organic base additionsalts of compounds of the present invention. These salts can likewise beprepared in situ during the final isolation and purification of thecompounds, or by separately reacting the purified compound in its freeacid form with a suitable base, such as the hydroxide, carbonate orbicarbonate of a pharmaceutically-acceptable metal cation, with ammonia,or with a pharmaceutically-acceptable organic primary, secondary ortertiary amine. Representative alkali or alkaline earth salts includethe lithium, sodium, potassium, calcium, magnesium, and aluminum saltsand the like. Representative organic amines useful for the formation ofbase addition salts include ethylamine, diethylamine, ethylenediamine,ethanolamine, diethanolamine, piperazine and the like. (See, forexample, S. M. Berge et al., "Pharmaceutical Salts," supra.)

In another aspect, the present invention providespharmaceutically-acceptable compositions which comprise atherapeutically-effective amount of one or more of the compounds ofFormula I, as described hereinabove, formulated together with one ormore pharmaceutically-acceptable carriers. As described in detail below,the pharmaceutical compositions of the present invention may bespecially formulated for oral administration in solid or liquid form,for parenteral injection, or for rectal or vagina administration.

In yet a further aspect, the present invention provides a method foreliminating or ameliorating pain in an animal comprising administering atherapeutically-effective amount of a compound of Formula I, asdescribed hereinabove, to the animal.

(3) Utility

By virtue of their analgesic activity, the compounds of the presentinvention, and the pharmaceutical compositions comprising one or more ofthese compounds, are useful as analgesic agents for the elimination oramelioration of pain in animals.

(4) Methods of Preparation

In general, the compounds of the present invention may be prepared bythe methods illustrated in the following general reaction schemes, or bymodifications thereof, using readily available starting materials,reagents and conventional synthetic procedures. In these reactions, itis also possible to make use of variants which are in themselves known,but are not mentioned here.

Unless otherwise specified, the various substituents of the compoundsshown in the general reaction schemes are defined in the same manner asthey are defined above in Formula I in the "Summary of Invention"section.

If a particular enantiomer of a compound of the present invention isdesired, it may be prepared by asymmetric synthesis, or byderivatization with a chiral auxiliary, where the resultingdiastereomeric mixture is separated and the auxiliary group cleaved toprovide the pure desired enantiomers. Alternatively, where the moleculecontains a basic functional group, such as amino, or an acidicfunctional group, such as carboxyl, diastereomeric salts are formed withan appropriate optically-active acid or base, followed by resolution ofthe diastereomers thus formed by fractional crystallization orchromatographic means well known in the art, and subsequent recovery ofthe pure enantiomers.

In General Reaction Scheme No. 1, a substituted or unsubstituted diamineis reacted with one equivalent of para-toluenesulfonic acid and oneequivalent of benzyloxy chloroformate. The resulting monoN-benzyloxycarbonyl protected diamine is treated with an `activated`N-Boc protected o-amino acid. The two methods of amino acid activationused are: (1) mixed anhydride coupling, which involves treatment of theacid with one equivalent each of N-methylmorpholine andisobutylchloroformate; and (2) carbodiimide coupling, which involvestreatment of the acid with the appropriate amine,dicyclohexylcarbodiimide and hydroxybenzotriazole. Both of these methodsof amino acid activation are known by those of skill in the art. Theproduct of this reaction is either treated with acid to remove the Bocprotecting group or treated with hydrogen in the presence of palladiumon carbon to give Compounds A. Compounds A are also obtained in one stepby the coupling of the N-Boc protected α-amino acid with an unprotecteddiamine in the presence of one equivalent of para-toluenesulfonic acid.Compounds A are coupled to an `activated` N-benzyloxycarbonyl protectedα-amino acid to give Compounds B. Compounds B are either treated withacid to remove the Boc protecting group or treated with hydrogen in thepresence of palladium on carbon to give Compounds C. The amino group inCompounds A and C are suitably functionalized as outlined in thisscheme, and as illustrated in the examples, to give a variety ofcompounds. Thus, for example, treatment of the amines with isocyanatesgave urea-type compounds, and treatment of the amines with activatedacids gave amide-type compounds. The resulting products of thesefunctionalization reactions are treated with acid to provide the saltsof the diamides indicated in Formula I.

General Reaction Scheme No. 2 outlines alternative and complementaryprocedures used for synthesizing compounds of this invention. Thus, inthis scheme, a diamine is coupled to two α-amino acids in successionusing a carbodiimide coupling procedure or mixed anhydride couplingprocedure to afford the Compounds D. When R¹⁶ =acetyl, Compounds D aretreated with acid to remove the Boc protecting group; when, in R16,W=oxygen and R¹⁷ =benzyl, Compounds D are identical to Compounds B inGeneral Reaction Scheme No. 1, and are treated in a similar fashion.##STR17##

The following letters correspond to the same letters employed in GeneralReaction Scheme No. 1:

a) One equivalent each of para-toluenesulfonic acid andbenzyloxychloroformate (Z=benzyloxycarbonyl).

b) Isobutyl chloroformate, N-methylmorpholine (mixed anhydride coupling)or dicyclohexyl carbodiimide and hydroxybenzotriazole (carbodiimidecoupling).

c) Hcl in dioxane-acetic acid or HCl in dioxane-CH₂ Cl₂.

d) Hydrogen/Palladium on Carbon.

e) Introduce R¹⁶ group

For R¹⁶ =trifluoroacetyl:

(1) trifluoracetic anhydride, dimethylaminopyridine, N-methylmorpholinein CH₂ Cl₂ ; and

(2) 15% K₂ CO₃ in MeOH.

For R¹⁶ =acetyl:

(1) acetic anhydride, dimethylaminopyridine, N-methylmorpholine in CH₂Cl₂ ; and

(2) 15% K₂ CO₃ in MeOH.

For R¹⁶, where W=CH₂ and R¹⁷ =alkyl or alkaryl: treat Compounds A withalkyl or alkaryl carboxylic acids under mixed anhydride couplingconditions (see "b" above).

For R¹⁶, where W=NH and Ru¹⁷ =alkyl, alkenyl or alkylcarboalkoxy: treatCompounds A with alkyl, alkenyl, or carboxyalkyl alkyl isocyanate.

For R¹⁶, where W=NH and Ru¹⁷ =sulfonylaryl: treat Compounds A witharylsulfonylisocyanate. ##STR18##

The following letters correspond to the same letters employed in GeneralReaction Scheme No. 2:

a) Isobutylchloroformate, N-methylmorpholine (mixed anhydride coupling)or dicyclohexylcarbodiimide and hydroxybenzotriazole (carbodiimidecoupling) in the presence of one equivalent of para-toluenesulfonicacid.

b) Identical coupling conditions are used as in "a" above, except thatpara-toluenesulfonic acid was not used. The Compounds D obtained areidentical to the Compounds B of General Reaction Scheme No. 1 Where, inR¹⁶, W=oxygen and R¹⁷ =benzyl. Compounds B here and in General ReactionScheme No. 1 are used in an identical fashion to afford the varioustarget structures represented by Compounds C.

c) When R¹⁶ =acetyl, Compounds D were treated with HCl in dioxane toremove the Boc protecting group. In R¹⁶, Where W=oxygen and R¹⁷ =benzyl,Compounds D are identical to Compounds B of General Reaction Scheme No.1 and are treated in like fashion.

The conditions for carrying out the individual steps in each of thegeneral reaction schemes presented above are conventional, well-known,and capable of wide variation.

Other methods known in the art can also be used to synthesize thecompounds of the present invention.

(5) Dosage and Mode of Administration

The compounds of the present invention, and the pharmaceuticalcompositions comprising one or more of these compounds in combinationwith a pharmaceutically-acceptable carrier, are useful for treating painin animals. A physician or veterinarian of ordinary skill in the art canreadily determine whether or not a patient is in pain.

The pharmaceutical compositions of the present invention, which willtypically comprise one or more of the compounds of Formula I, asdescribed in the "Summary of Invention" section, as an active ingredientin a mixture with one or more pharmaceutically-acceptable carriers and,optionally, with one or more other compounds, drugs or materials, areemployed therapeutically and, thus, would generally be used under theguidance of a physician. The appropriate dosage and form ofadministration of these compositions will be suitably selected bymethods which are consistent with conventional pharmaceutical practices.

The pharmaceutical compositions of the present invention may bespecially formulated for oral administration in solid or liquid form,for parenteral injection, and/or for rectal or vaginal administration.These compounds may be administered to humans and other animals fortherapy by any suitable route of administration, including orally,nasally, as by, for example, a spray, rectally, intravaginally,parenterally, intracisternally and topically, as by powders, ointmentsor drops, including buccally and sublingually. While the preferredroutes of administration are oral and subcutaneous, the most preferredmode of administration is subcutaneous.

Regardless of the route of administration selected, the compounds of thepresent invention, which may be used in a suitable hydrated form, and/orthe pharmaceutical compositions of the present invention, are formulatedinto pharmaceutically-acceptable dosage forms by conventional methodsknown to those of skill in the art.

Actual dosage levels of the active ingredients in the pharmaceuticalcompositions of this invention may be varied so as to obtain an amountof the active ingredient which is effective to achieve the desiredtherapeutic response for a particular patient, composition, and mode ofadministration, without being toxic to the patient.

The selected dosage level will depend upon a variety of factorsincluding the activity of the particular compound of the presentinvention employed, or the ester, salt or amide thereof, the route ofadministration, the time of administration, the rate of excretion of theparticular compound being employed, the severity of the pain, theduration of the treatment, other drugs, compounds and/or materials usedin combination with the particular compound employed, the age, sex,weight, condition, general health and prior medical history of thepatient being treated, and like factors well known in the medical arts.

A physician or veterinarian having ordinary skill in the art can readilydetermine and prescribe the effective amount of the pharmaceuticalcomposition required to alleviate or ameliorate a particular patient'spain. For example, the physician or veterinarian could start doses ofthe compound of the invention employed in the pharmaceutical compositionat levels lower than that required in order to achieve the desiredtherapeutic effect and gradually increase the dosage until the desiredeffect is achieved.

In general, a suitable daily dose of a compound of the invention will bethat amount of the compound which is the lowest dose effective toproduce a therapeutic effect. Such an effective dose will generallydepend upon the factors described above. Generally, intravenous,intracerebroventricular and subcutaneous doses of the compounds of thisinvention for a patient, when used for the indicated analgesic effects,will range from about 0.0001 to about 100 mg per kilogram of body weightper day. If desired, the effective daily dose of the active compound maybe administered as two, three, four, five, six or more sub-dosesadministered separately at appropriate intervals throughout the day,optionally, in unit dosage forms.

While it is possible for a compound of the present invention to beadministered alone, it is preferable to administer the compound as apharmaceutical formulation (composition).

The pharmaceutical compositions of the present invention comprise acompound of the present invention together with one or morepharmaceutically-acceptable carriers thereof and, optionally, with othertherapeutic agents. Each carrier must be "acceptable" in the sense ofbeing compatible with the other ingredients of the formulation and notinjurious to the patient.

Wetting agents, emulsifiers and lubricants, such as sodium laurylsulfate and magnesium stearate, as well as coloring agents, releasingagents, coating agents, sweetening, flavoring and perfuming agents,preservatives and antioxidants can also be present in the compositions.

Examples of pharmaceutically-acceptable antioxidants include: (1) watersoluble antioxidants, such as ascorbic acid, cysteine hydrochloride,sodium bisulfate, sodium metabisulfite, sodium sulfite and the like; (2)oil-soluble antioxidants, such as ascorbyl palmitate, butylatedhydroxyanisole (BHA), butylated hydroxytoluene (BHT), lecithin, propylgallate, alpha-tocopherol, and the like; and (3) metal chelating agents,such as citric acid, ethylenediaminetetraacetic acid (EDTA), sorbitol,tartaric acid, phosphoric acid, and the like.

Formulations of the present invention include those suitable for oral,nasal, topical (including buccal and sublingual), rectal, vaginal and/orparenteral administration. The formulations may conveniently bepresented in unit dosage form and may be prepared by any methods wellknown in the art of pharmacy. The amount of active ingredient (compoundof Formula I) which can be combined with a carrier material to produce asingle dosage form will vary depending upon the host being treated, theparticular mode of administration and all of the other factors describedabove. The amount of active ingredient which can be combined with acarrier material to produce a single dosage form will generally be thatamount of the compound which produces a therapeutic effect. Generally,out of one hundred per cent, this amount will range from about 1 percent to about ninety-nine percent of active ingredient, preferably fromabout 5 per cent to about 70 per cent, most preferably from about 10 percent to about 30 per cent.

Methods of preparing these formulations or compositions include the stepof bringing into association a compound of the present invention withthe carrier and, optionally, with one or more accessory ingredients. Ingeneral, the formulations are prepared by uniformly and intimatelybringing into association a compound of the present invention withliquid carriers, or finely divided solid carriers, or both, and then, ifnecessary, shaping the product.

Formulations of the invention suitable for oral administration may be inthe form of capsules, cachets, pills, tablets, lozenges (using aflavored basis, usually sucrose and acacia or tragacanth), powders,granules, or as a solution or a suspension in an aqueous or non-aqueousliquid, or as an oil-in-water or water-in-oil liquid emulsion, or as anelixir or syrup, or as pastilles (using an inert base, such as gelatinand glycerin, or sucrose and acacia) and/or as mouth washes and thelike, each containing a predetermined amount of a compound of thepresent invention as an active ingredient. A compound of the presentinvention may also be administered as a bolus, electuary or paste.

In solid dosage forms of the invention for oral administration(capsules, tablets, pills, dragees, powders, granules and the like), theactive ingredient (compound of Formula I) is mixed with one or morepharmaceutically-acceptable carriers, such as sodium citrate ordicalcium phosphate, and/or any of the following: (1) fillers orextenders, such as starches, lactose, sucrose, glucose, mannitol, and/orsilicic acid; (2) binders, such as, for example, carboxymethylcellulose,alginates, gelatin, polyvinyl pyrrolidone, sucrose and/or acacia; (3)humectants, such as glycerol; (4) disintegrating agents, such asagar-agar, calcium carbonate, potato or tapioca starch, alginic acid,certain silicates, and sodium carbonate; (5) solution retarding agents,such as paraffin; (6) absorption accelerators, such as quaternaryammonium compounds; (7) wetting agents, such as, for example, cetylalcohol and glycerol monostearate; (8) absorbents, such as kaolin andbentonite clay; (9) lubricants, such as talc, calcium stearate,magnesium stearate, solid polyethylene glycols, sodium lauryl sulfate,and mixtures thereof; and (10) coloring agents. In the case of capsules,tablets and pills, the pharmaceutical compositions may also comprisebuffering agents. Solid compositions of a similar type may also beemployed as fillers in soft and hard-filled gelatin capsules using suchexcipients as lactose or milk sugars, as well as high molecular weightpolyethylene glycols and the like.

A tablet may be made by compression or molding, optionally with one ormore accessory ingredients. Compressed tablets may be prepared usingbinder (for example, gelatin or hydroxypropylmethyl cellulose),lubricant, inert diluent, preservative, disintegrant (for example,sodium starch glycolate or cross-linked sodium carboxymethyl cellulose),surface-active or dispersing agent. Molded tablets may be made bymolding in a suitable machine a mixture of the powdered compoundmoistened with an inert liquid diluent.

The tablets, and other solid dosage forms of the pharmaceuticalcompositions of the present invention, such as dragees, capsules, pillsand granules, may optionally be scored or prepared with coatings andshells, such as enteric coatings and other coatings well known in thepharmaceutical-formulating art. They may also be formulated so as toprovide slow or controlled release of the active ingredient thereinusing, for example, hydroxypropylmethyl cellulose in varying proportionsto provide the desired release profile, other polymer matrices,liposomes and/or microspheres. They may be sterilized by, for example,filtration through a bacteria-retaining filter, or by incorporatingsterilizing agents in the form of sterile solid compositions which canbe dissolved in sterile water, or some other sterile injectable mediumimmediately before use. These compositions may also optionally containopacifying agents and may be of a composition that they release theactive ingredient(s) only, or preferentially, in a certain portion ofthe gastrointestinal tract, optionally, in a delayed manner. Examples ofembedding compositions which can be used include polymeric substancesand waxes. The active ingredient can also be in micro-encapsulated form,if appropriate, with one or more of the above-described excipients.

Liquid dosage forms for oral administration of the compounds of theinvention include pharmaceutically acceptable emulsions, microemulsions,solutions, suspensions, syrups and elixirs. In addition to the activeingredient (compound of Formula I), the liquid dosage forms may containinert diluents commonly used in the art, such as, for example, water orother solvents, solubilizing agents and emulsifiers, such as ethylalcohol, isopropyl alcohol, ethyl carbonate, ethyl acetate, benzylalcohol, benzyl benzoate, propylene glycol, 1,3-butylene glycol, oils(in particular, cottonseed, groundnut, corn, germ, olive, castor andsesame oils), glycerol, tetrahydrofuryl alcohol, polyethylene glycolsand fatty acid esters of sorbitan, and mixtures thereof.

Besides inert diluents, the oral compositions can also include adjuvantssuch as wetting agents, emulsifying and suspending agents, sweetening,flavoring, coloring, perfuming and preservative agents.

Suspensions, in addition to the active compounds, may contain suspendingagents as, for example, ethoxylated isostearyl alcohols, polyoxyethylenesorbitol and sorbitan esters, microcrystalline cellulose, aluminummetahydroxide, bentonite, agar-agar and tragacanth, and mixturesthereof.

Formulations of the pharmaceutical compositions of the invention forrectal or vaginal administration may be presented as a suppository,which may be prepared by mixing one or more compounds of the inventionwith one or more suitable nonirritating excipients or carrierscomprising, for example, cocoa butter, polyethylene glycol, asuppository wax or a salicylate, and which is solid at room temperature,but liquid at body temperature and, therefore, will melt in the rectumor vaginal cavity and release the active compound.

Formulations of the present invention which are suitable for vaginaladministration also include pessaries, tampons, creams, gels, pastes,foams or spray formulations containing such carriers as are known in theart to be appropriate.

Dosage forms for the topical or transdermal administration of a compoundof this invention include powders, sprays, ointments, pastes, creams,lotions, gels, solutions, patches and inhalants. The active compound maybe mixed under sterile conditions with a pharmaceutically-acceptablecarrier, and with any preservatives, buffers, or propellants which maybe required.

The ointments, pastes, creams and gels may contain, in addition to anactive compound of this invention, excipients, such as animal andvegetable fats, oils, waxes, paraffins, starch, tragacanth, cellulosederivatives, polyethylene glycols, silicones, bentonites, silicic acid,talc and zinc oxide, or mixtures thereof.

Powders and sprays can contain, in addition to a compound of thisinvention, excipients such as lactose, talc, silicic acid, aluminumhydroxide, calcium silicates and polyamide powder, or mixtures of thesesubstances. Sprays can additionally contain customary propellants, suchas chlorofluorohydrocarbons and volatile unsubstituted hydrocarbons,such as butane and propane.

Transdermal patches have the added advantage of providing controlleddelivery of a compound of the invention to the body. Such dosage formscan be made by dissolving or dispersing the compound in the propermedium. Absorption enhancers can also be used to increase the flux ofthe compound across the skin. The rate of such flux can be controlled byeither providing a rate controlling membrane or dispersing the compoundin a polymer matrix or gel.

Ophthalmic formulations, eye ointments, powders, solutions and the like,are also contemplated as being within the scope of this invention.

Pharmaceutical compositions of this invention suitable for parenteraladministration comprise one or more compounds of the invention incombination with one or more pharmaceutically-acceptable sterileisotonic aqueous or nonaqueous solutions, dispersions, suspensions oremulsions, or sterile powders which may be reconstituted into sterileinjectable solutions or dispersions just prior to use, which may containantioxidants, buffers, bacteriostats, solutes which render theformulation isotonic with the blood of the intended recipient orsuspending or thickening agents.

Examples of suitable aqueous and nonaqueous carriers which may beemployed in the pharmaceutical compositions of the invention includewater, ethanol, polyols (such as glycerol, propylene glycol,polyethylene glycol, and the like), and suitable mixtures thereof,vegetable oils, such as olive oil, and injectable organic esters, suchas ethyl oleate. Proper fluidity can be maintained, for example, by theuse of coating materials, such as lecithin, by the maintenance of therequired particle size in the case of dispersions, and by the use ofsurfactants.

These compositions may also contain adjuvants such as preservatives,wetting agents, emulsifying agents and dispersing agents. Prevention ofthe action of microorganisms may be ensured by the inclusion of variousantibacterial and antifungal agents, for example, paraben,chlorobutanol, phenol sorbic acid, and the like. It may also bedesirable to include isotonic agents, such as sugars, sodium chloride,and the like into the compositions. In addition, prolonged absorption ofthe injectable pharmaceutical form may be brought about by the inclusionof agents which delay absorption, such as aluminum monostearate andgelatin.

In some cases, in order to prolong the effect of a drug, it is desirableto slow the absorption of the drug from subcutaneous or intramuscularinjection. This may be accomplished by the use of a liquid suspension ofcrystalline or amorphous material having poor water solubility. The rateof absorption of the drug then depends upon its rate of dissolutionwhich, in turn, may depend upon crystal size and crystalline form.Alternatively, delayed absorption of a parenterally-administered drugform is accomplished by dissolving or suspending the drug in an oilvehicle.

Injectable depot forms are made by forming microencapsule matrices ofthe drug in biodegradable polymers such as polylactide-polyglycolide.Depending on the ratio of drug to polymer, and the nature of theparticular polymer employed, the rate of drug release can be controlled.Examples of other biodegradable polymers include poly(orthoesters) andpoly(anhydrides). Depot injectable formulations are also prepared byentrapping the drug in liposomes or microemulsions which are compatiblewith body tissue.

The injectable materials can be sterilized, for example, by filtrationthrough a bacterial-retaining filter, or by incorporating sterilizingagents in the form of sterile solid compositions which can be dissolvedor dispersed in sterile water or in other sterile injectable mediumsjust prior to use.

The formulations may be presented in unit-dose or multi-dose sealedcontainers, for example, ampoules and vials, and may be stored in alyophilized condition requiring only the addition of the sterile liquidcarrier, for example water for injections, immediately prior to use.Extemporaneous injection solutions and suspensions may be prepared fromsterile powders, granules and tablets of the type described above.

The pharmaceutical compositions of the present invention may also beused in the form of veterinary formulations, including those adapted forthe following: (I) oral administration, for example, drenches (aqueousor non-aqueous solutions or suspensions), tablets, boluses, powders,granules or pellets for admixture with feed stuffs, pastes forapplication to the tongue; (2) parenteral administration, for example,by subcutaneous, intramuscular or intravenous injection as, for example,a sterile solution or suspension or, when appropriate, by intramammaryinjection where a suspension or solution is introduced into the udder ofthe animal via its teat; (3) topical application, for example, as acream, ointment or spray applied to the skin; or (4) intravaginally, forexample, as a pessary, cream or foam.

While the various aspects of the present invention are described hereinwith some particularity, those of skill in the art will recognizenumerous modifications and variations which remain within the spirit ofthe invention. These modifications and variations are within the scopeof the invention as described and claimed herein.

(6) Examples

The following non-limiting examples describe and illustrate the methodsfor the preparation of the compounds of the present invention, as wellas other aspects of the present invention, and the results achievedthereby, in further detail. Both an explanation of, and the actualprocedures for, the various aspects of the present invention aredescribed where appropriate. These examples are intended to be merelyillustrative of the present invention, and not limiting thereof ineither scope or spirit. Those of skill in the art will readilyunderstand that known variations of the conditions and processes of thepreparative procedures described in these examples can be used toprepare the compounds of the present invention, and the pharmaceuticalcompositions comprising such compounds.

All patents and publications referred to in the examples, and throughoutthe specification, are hereby incorporated herein by reference, withoutadmission that such is prior art.

In the examples, all parts are by weight, and all temperatures aredegrees Celsius, unless otherwise noted. Unless otherwise noted,Infrared (IR) and Nuclear Magnetic Resonance (NMR) spectra wereconsistent with the assigned structure.

Unless otherwise indicated, all of the equipment employed in theexamples is commercially available.

All starting materials used in the examples are commercially available,and were obtained from Aldrich Chemical Co. (Milwaukee, Wis.), TCIAmerican Tokyo (Portland, Oreg.), Advanced Chemtech (Louisville, Ky.),Fluka Chemical Corp. (Ronkonkoma, N.Y.), Bachem Bioscience Inc.(Philadelphia, Pa.), Chemical Dynamics Corp. (South Plainfield, N.J.),Sigma Chemical Co. (St. Louis, Mo.) and/or Peptides International(Louisville, Ky.).

While Examples 1-59 describe specific methods for synthesis of compoundswithin the present invention, Examples 60-62 describe four differentassays which were conducted with compounds of the present invention.

Examples 60 (Writhing Assay) and 61 (Tail Flick and Hot Plate Assays)describe experiments which were conducted to compare the analgesicactivity of tyrosyl diamide compounds described herein with a compounddescribed by A. R. Jacobson et al., supra., designated the "JacobsonCompound," in different analgesic assays, as described in detailhereinbelow.

The structure of the Jacobson Compound is shown below. ##STR19##

The tyrosyl diamide compound which is shown and described in Example 47was tested in each of the following three analgesic assays, as describedin Examples 60 and 61 hereinbelow: (1) the Writhing Assay; (2) the TailFlick Assay; and (3) the Hot Plate Assay. These assays were performed inthe manner described in Examples 60 and 61 hereinbelow. This compound,as well as the Jacobson Compound, was administered to the mice employedin these assays subcutaneously or orally, as indicated in the tables ofdata presented in Examples 60 and 61 hereinbelow.

Example 62 describes the evaluation of compounds within the presentinvention, as well as the Jacobson Compound, in an opioid radioligandbinding assay, which measures the affinity of opioids for specificopioid receptors in rat forebrain, by their ability to displace thebinding of radiolabeled ligands specifically bound to μ and/or δ opioidreceptors isolated from rat brain.

Example 1 Phenylmethyl(2-amino-2-methyloropyl)carbamate ##STR20##

A solution of benzyloxychloroformate (3.9 g) in toluene (15 mL) wasadded dropwise to a stirred solution of 1,2-diamino-2-methylpropane (5g) in toluene (90 mL) at 0° C for 20 minutes. After 40 hours, thereaction mixture was filtered. The filtrate was concentrated in vacuo.The residue was redissolved in toluene and stripped of all solventseveral times. The residue was dried in vacuo to give the title compoundas a white solid (4.3 g), which was used in Example 2 without furtherpurification.

Example 2Phenylmethyl[2-[2S-[[(1,1-dimethylethoxy)carbonyl]-amino]-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]-amino]-2-methyloropyl]carbamate##STR21##

To a stirred solution of Boc-2,6-L-dimethyltyrosine (Boc-DMT, 13.9 g) inmethylene chloride (CH₂ Cl₂, 600 mL) at -78° C. was addedN-methylmorpholine (NMM, 4.9 mL) followed by isobutylchloroformate(IBCF, 6.1 mL). The mixture was allowed to warm to 0° C. over 25 minutesand was then recooled to -78° C. To this was added the title compound ofExample 1 (10 g), and stirring was continued for 48 hours. The mixturewas concentrated in vacuo. The residue was dissolved in ethyl acetate(EtOAc), washed with 0.5 N KHSO₄, dried over Na₂ SO₄, and concentratedin vacuo. The residue was purified by chromatography over silica gelusing 5% ethanol in 8:11 CH₂ Cl₂ /n-hexane as eluant to give 8.9 g ofthe title compound as a white solid.

Example 3

Phenylmethyl[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyllamino]-2-methylpropyl]-carbamate, monohydrochloride##STR22##

The title compound of Example 2 (0.4 g) was dissolved in 10 mL of aceticacid (HOAc) and 1.2 mL of 7 N hydrogen chloride (7 N HCl) in dioxane.The resulting solution was allowed to stir at room temperature for 30minutes. The volatiles were removed in vacuo. The residue was trituratedwith diethyl ether (Et₂ O), filtered and dried in vacuo to give thetitle compound as a white solid.

Calculated for C₂₃ H₃₂ N₃ O₄ +0.4 H₂ O+HCl (MW=457.18): C, 60.43; H,7.23; N, 9.19; Cl, 7.75. Found: C, 60.45; H, 7.22; N, 8.86; Cl, 7.67.

[α]_(D) =+69.5°, MeOH.

Example 4 Compound A1,1-Dimethylethyl[1S-[[(2-amino-1,1-dimethylethyl)amino]carbonyl]-2-(4-hydroxy-2,6-dimethylphenyl)ethyl]carbamate##STR23## Compound B1,1-Dimethylethyl[2-[(2-amino-2-methylpropyl)amino]-1S-[(4-hydroxy-2,6-dimethylphenyl)methyl]-2-oxoethyl]carbamate ##STR24##

The title compound of Example 2 (6.07 g) was subjected to hydrogenationby a standard Parr apparatus in 100 mL of methanol (MeOH) with 4% Pd oncarbon under 5 psi hydrogen for 16 hours. The mixture was filtered toremove the catalyst. The filtrate was concentrated to dryness to leave4.3 g of a mixture of the title compounds as white solids.

Example 51,1-Dimethylethyl[1S-[[[2-[[2S-(acetylamino)-3-(4-fluorophenyl)-1-oxopropyl]amino]-I,1-dimethylethyl]amino]carbonyl]-2-(4-hydroxy-2,6-dimethylphenyl)ethyl]carbamate##STR25##

The product mixture of the title compounds of Example 4 was coupled toN-acetyl-L-p-fluoro-phenylalanine using the mixed anhydride couplingmethod as described in Example 2 above. The crude product waschromatographed over silica gel to give only the title compound as awhite solid.

Example 6αS-(Acetylamino)-N-2-[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methyloropyl]-4-fluorobenzenepropanamide,monohydrochloride ##STR26##

The title compound of Example 5 was treated with HCl by the procedure ofExample 3 to give the title compound as a white solid salt.

Calculated for: C₂₆ H₃₅ N₄ O₄ F₁ +1 H₂ O+1 HCl (MW=541.07): C, 57.72; H,7.08; N, 10.35; Cl, 6.55. Found: C, 57.90; H, 6.98; N, 9.93; Cl, 6.57.

[α]_(D) =+77.6°, MeOH.

H¹ NMR CD₃ OD)δ: 0.94 (s, 3H), 1.15 (s, 3H), 2.28 (s, 6H).

Example 7Phenylmethyl[1S-[[[2-[[2S-[[(1,1-dimethylethoxy)-carbonyl]amino]-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyllamino]carbonyl]-2-(4-fluorophenyl)ethyl]carbamate ##STR27##

The product mixture of the title compounds of Example 4 was coupled toN-benzyloxycarbonyl-L-para-fluoro-phenylalanine using the mixedanhydride coupling method as described in Example 2 above. The crudeproduct was chromatographed over silica gel to give only the titlecompound as a white solid.

Example 8Phenylmethyl[1S-[[[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylohenyl)-1-oxopropyllamino]-methylpropyl]amino]-carbonyl]-2-(4-fluorophenyl)ethyl]carbamate. monohydrochloride ##STR28##

The title compound of Example 7 was treated with HCl by the procedure ofExample 3 to give the title compound as a white solid.

Calculated for: C₃₂ H₃₉ N₄ O₅ F_(l) +0.5 H₂ O+1 HCl (MW=624.16): C,61.58; H, 6.62; N, 8.98; Cl, 5.68. Found: C, 61.49; H, 6.53; N, 8.77;Cl, 5.76.

[α]_(D) =+15.7°, MeOH.

H¹ NMR (CD₃ OD)δ: 0.9 (s, 3H), 1.2 (s, 3H), 2.3 (s, 6H).

EXAMPLE 9

Phenylmethyl[1S-[[[2-[[2S-[[(1,1-dimethylethoxy)-carbonyl]amino]-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyllamino]carbonyl]-2-phenylethyl]carbamate##STR29##

1,2-Diamino-2-methylpropane was coupled to benzyloxycarbonylZ-phenylalanine and Boc-DMT in succession using the protocol of A. R.Jacobson et al., supra., which is incorporated herein by reference, togive the title compound as a white solid.

Briefly, to 15 mL of DMF was added 1.43 g of z-phenylalanine-OH, 426 mgof 1,2-diamino-2-methylpropane, 920 mg of para-toluenesulfonic acid monohydrate and 652 mg of 1-hydroxybenzotriazole. After allowing the mixtureto mix for 5 minutes, 1.1 g of 1,3-dicyclohexylcarbodiimide was addedand the reaction was mixed overnight at room temperature. The solventwas removed in vacuo and 50 mL of CHCl₃ was added. The mixture was thenfiltered and extracted with two 20-mL portions of half-saturated aqueousNa₂ CO₃. The organic layer was concentrated in vacuo giving 625 mg of awhite solid. To a 20-mL CH₂ Cl₂ solution of this solid was added 0.494 gof Boc-DMT and 0.220 g of I-hydroxybenzotriazole hydrate. After stirringfor 5 minutes, 0.33 g of 1,3-dicyclohexylcarbodiimide was added and thereaction mixture was allowed to warm to room temperature overnight withmixing. After filtration, the mother liquor was washed with two 20-mLportions of half-saturated Na₂ CO₃ and evaporated to dryness in vacuo togive 1 g of the title compound as a white solid.

Example 10

Phenylmethyl[1S-[[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylohenyl)-1-oxopropyl]amino]-2-methylpropyl]-amino]carbonyl]-2-phenylethyl]carbamate,monohydrochloride ##STR30##

The title compound of Example 9 was treated with HCl by the procedure ofExample 3 to give the title compound as a white solid.

Calculated for C₃₂ H₄₀ N₄ O₅ +HCl+0.5 H₂ O(MW=606.17): C, 63.41; H,6.98; N, 9.24; Cl, 5.85. Found: C, 63.30; H, 7.04; N, 9.08; Cl, 6.33.

[α]_(D) =+69.4°, MeOH.

H¹ NMR (CD₃ OD)δ: 0.9 (s, 3 H), 1.2 (s, 3 H), 2.3 (s, 6 H), 6.6 (s, 2H).

Example 11 1,1-Dimethylethyl[1S-[[[2-[(2S-amino-1-oxo-3-phenylpropyl)amino-2-methylpropyl]amino]-carbonyl]-2-(4-hydroxy-2,6-dimethylphenyl)ethyl]-carbamate,acetic acid salt ##STR31##

Removal of the benzyloxycarbonyl (Z) protecting group from the productof Example 9 was accomplished by hydrogenation in MeOH, as described inExample 4 above to give a free base. This material was dissolved inHOAc, and the solution was concentrated in vacuo to give the titlecompound as a white solid.

Calculated for C₃₁ H₄₆ N₄ O₇ +2 HOAc (MW=646.78): C, 61.28; H, 7.79; N,8.66. Found: C, 61.36; H, 7 98; N, 8.61.

[α]_(D) =+48.3° , MeOH.

H¹ NMR (CD₃ OD)δ:2.3 (s, 6 H), 6.5 (s, 2 H).

Example 12

αS-amino-N-[2-[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]benzenepropanamide, dihydrochloride##STR32##

The title compound of Example 11 was treated with HCl by the procedureof Example 3 to give the title compound as a white solid.

Calculated for C₂₄ H₃₄ N₄ O₃ +2HCl+H₂ O(MW=517.50): C, 55.70; H, 7.40;N, 10.83; Cl, 13.70. Found: C, 56.00; H, 7.16; N, 10.59; Cl, 13.73.

[α]_(D) =+117.6°, MeOH.

H¹ NMR (CD₃ OD)δ:0.9 (s, 3 H), 1.2 (s, 3 H), 2.3 (s, 6 H), 6.5 (s, 6 H).

Example 13 1,1-Dimethylethyl[1S-[[2-[[1,1-dimethyl-2-[1-oxo-3-phenyl-2S-[(trifluoroacetyl)amino]propyl]amino]ethyl]-amino]carbonyl]-2-(4-hydroxy-2,6-dimethylphenyl)ethyl]-carbamate##STR33##

To a stirred solution of the title compound of Example 11 (0.5 g) in CH₂Cl₂ (25 mL) was added NMM (0.2 g), 4-dimethylamino-pyridine (6 mg) andtrifluoroacetic anhydride (0.8 g). After 2 hours, the mixture was washedwith 0.5 N KHSO₄, dried over MgSO₄ and concentrated in vacuo. Theresidue was washed with hexane to leave a white solid. This solid wasstirred in methanol (30 mL) and 2.5 mL of 15% aqueous K₂ CO₃ for 16hours. The mixture was filtered and the filtrate concentrated in vacuo.The residue was dissolved in CH₂ Cl₂ and the solution was washed withwater, dried over MgSO₄ and concentrated in vacuo to give the titlecompound as a white solid.

Example 14

αS-Amino-N-[1,1-dimethyl-2-[[1-oxo-3-phenyl-2S-[[trifluoroacetyl-amino]propyl]aminoethyl]-4-hydroxy-2,6-dimethylbenzenepropanamide,hydrochloride ##STR34##

The title compound of Example 13 was treated with HCl by the procedureof Example 3 to give the title compound as a white solid.

Calculated for C₂₆ H₃₃ F₃ N₄ O₄ +1.2 HCl+0.3 H₂ O (MW=571.73): C, 54.62;H, 6.14; N, 9.80; Cl, 7.44 Found: C, 54.64; H, 6.07; N, 9.71; Cl, 7.40.

[α]_(D) =+85.2° , MeOH.

H¹ NMR CD₃ OD)δ:0.8 (s, 3 H), 1.2 (s, 3 H), 2.2 (s, 6 H), 6.5 (s, 2 H).

Example 15

1,1-Dimethylethyl[1S-[[[2-[[2S-(acetylamino)-1-oxo-3-phenylpropyl]amino]-1,1-dimethylethyl]aminocarbonyl]-2-[4-(acetyloxy)-2,6-dimethylphenyl)lethyl]carbamate ##STR35##

To a stirred solution of the title compound of Example 11 (0.5 g) in CH₂Cl₂ (25 mL) at room temperature and under N2 was added NMM (0.2 g),4-dimethylaminopyridine (6 mg) and acetic anhydride (0.8 g). After 2hours, the mixture was washed with 0.5 N KHSO₄, dried over MgSO₄ andconcentrated in vacuo. The residue was washed with hexane to give thetitle compound as a white solid.

Example 16

αS-(acetylamino)-N-2-[2-[[4-(acetyloxy)-2,6-dimethylphenyl]-2S-amino-1-oxopropyl]amino]-2-methylpropyl]benzenepropanamide,hydrochloride ##STR36##

The title compound of Example 15 was treated with HCl by the procedureof Example 3 to give the title compound as a white solid.

Calculated for C₂₈ H₄₀ N₄ O₆ +1.1 HCl+H₂ O(MW=568.76): C, 59.24; H,7.12; N, 9.87; Cl, 6.87. Found: C, 59.45; H, 7.I2; N, 9.92; Cl, 6.92.

[α]_(D) =+99.0° , MeOH.

H¹ NMR CD₃ OD)δ:0.8 (s, 3 H), 1.2 (s, 3 H), 1.9 (s, 3 H), 2.2 (s, 3 H),2.3 (s, 3 H), 6.8 (s, 2 H).

Example 171,1-Dimethylethyl[1S-[[2-[2S-(acetylamino)-1-oxo-4-henylbutyl]amino]-1,1-dimethylethyl]amino]carbonyl]-2-(4-hydroxy-2,6-dimethylohenyl)ethyl]carbamate ##STR37##

1,2-Diamino-2-methylpropane was coupled to N-acetyl-homophenylalanineand Boc-DMT in succession using the protocol of A. R. Jacobson et al.,supra., described in Example 9 above to give the title compound as awhite solid.

Example 18αS-(acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylohenyl)-1-oxopropyl]amino]-2-methyloropyl]-benzenebutanamide,hydrochloride ##STR38##

The title compound of Example 17 was treated with HCl by the procedureof Example 3 to give the title compound as a white solid.

Calculated for C₂₇ H₃₈ N₄ O₄ +1.1 HCl+1.5 H₂ O(MW=549.76): C, 58.99; H,7.72; N, 10.19; Cl, 7.09 Found: C, 59.01; H, 7.45; N, 10.14; Cl, 7.27.

[α]_(D) =+44.6° , MeOH.

H¹ NMR (CD₃ CO₂ D δ: 0.9 (s, 3 H), 1.2 (s, 3 H), 2.2 (s, 6 H), 6.5 (s, 2H).

Example 191,1-Dimethylethyl[IS-[[[2-[[2S-(acetylamino)-I-oxo-2-phenylethyl]amino]-1,1-dimethylethyl]amino]carbonyl]-2-(4-hydroxy-2,6-dimethylphenyl)ethyl1 carbamate ##STR39##

1,2-Diamino-2-methylpropane was coupled to N-acetyl-phenylglycine andBoc-DMT in succession using the protocol of A. R. Jacobson et al.,supra., described in Example 9 above to give the title compound as awhite solid.

Example 20

N-[2-[[2S-(acetylamino)-2-phenylacetyl]amino]-1,1-dimethylethyl]-αS-amino-4-hydroxy-2,6-dimethylbenzenepropanamide,hydrochloride ##STR40##

The title compound of Example 19 was treated with HCl by the procedureof Example 3 to give the title compound as a white solid.

Calculated for C₂₅ H₃₄ N₄ O₄ +1.5 HCl+2 H₂ O(MW=545.30): C, 55.07; H,7.30; N, 10.27; Cl, 9.75. Found: C, 55.28; H, 6.91; N, 10.10; Cl, 9.59.

[α]_(D) =+116.0°, MeOH

H¹ NMR (CD₃ CO₂ D δ: 0.8 (s, 3 H), 1.2 (s, 3 H), 2.3 (s, 6 H), 6.5 (s, 2H).

Example 21Phenylmethyl[1S-[[[2-[[2S-[[(1,1-dimethylethoxy)carbonyl]amino]-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]ethyl]amino]carbonyl]-2-phenylethyl]carbamate##STR41##

Using 1,2-diamino-ethane in the place of 1,2-diamino-2-methylpropane inthe procedure of Example 9, the title compound was obtained as a whitesolid.

Example 22

Phenylmethyl[1S-[[(2-(8 [2S-amino-3-[4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]ethylaminocarbonyl-2-phenylethylcarbamate,monohydrochloride ##STR42##

The title compound of Example 21 was treated with HCl by the procedureof Example 3 to give the title compound as a white solid.

Calculated for C₃₀ H₃₆ N₄ O₅ +1 HCl+0.5 H₂ O(MW=578.11): C, 62.33; H,6.63; N, 9.69; Cl, 6.I3. Found: C, 62.54; H, 6.60; N, 9.53; Cl, 6.15.

[α]_(D) =+77.7°, MeOH.

H¹ NMR (CD₃ OD)δ:2.3 (s, 6 H), 6.5 (s, 2 H).

Example 23 1,1-dimethylethyl[1S-[[[2-[[(2S-amino-l-oxo-3-phenylpropyl)amino]ethyl]amino]carbonyl]-2-(4-hydroxy-2,6-dimethylohenyl)ethyl]carbamate, acetate (salt) ##STR43##

Removal of the Z protecting group from the title compound of Example 2Iwas accomplished by hydrogenation in methanol as described in Example 4to give a free base. This material was dissolved in acetic acid and thesolution was concentrated in vacuo to give the title compound as a whitesolid.

Calculated for C₂₉ H₄₂ N₄ O₇ +1.3 AcOH (MW=576.69): C, 61.65; H, 7.55;N, 9.72. Found: C, 61.59; H, 7.74; N, 9.39.

[α]_(D) =+28.4°, MeOH.

H¹ NMR CD₃ OD)δ:2.2 (s, 6 H), 6.5 (s, 2 H).

Example 24

αS-amino-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]ethyl]benzenepropanamide, dihydrochloride ##STR44##

The title compound of Example 23 was treated with HCl by the method ofExample 3 to give the title compound as a white solid.

Calculated for C₂₂ H₃₀ N₄ O₃ +2 HCl+H₂ O(MW=489.44): C, 53.99; H, 7.00;N, 11.45; Cl, 14.49. Found: C, 53.79; H, 6.83; N, 11 25; Cl, 14.99.

[α]_(D) =+72.8°, MeOH.

H¹ NMR (CD₃ OD)δ:2.2 (s, 6 H), 6.5 (s, 2 H).

Example 25 Compound APhenylmethyl[1S-[[[2-[[2S-[[(1,1-dimethylethoxy)carbonyl]amino]-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-1,1-dimethylethyl]amino]carbonyl]-2-phenylethyl]carbamate##STR45## Compound BPhenylmethyl[1S-[[[2-[[2S-[[(1,1-dimethylethoxy()carbonyl]amino]-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]amino]carbonyl]-2-phenylethyl]carbamate##STR46##

The product mixture of the title compounds of Example 4 was coupled toN-benzyloxycarbonyl-phenylalanine using the mixed anhydride proceduredescribed in Example 2 to give a mixture of the less polar titleCompound A and the more polar title Compound B as white solids. TitleCompound B is identical to the title compound of Example 9. The isomerswere separated by chromatography.

Compound A:

Calculated for C₃₇ H₄₈ N₄ O₇ +0.5 H₂ O(MW=669.82): C, 66.35; H, 7.37; N,8.36. Found: C, 66.30; H, 7.37; N, 8.28.

[α]_(D) =+28.4°, CHCl₃.

Compound B: Identical to the title compound of Example 9.

Example 26Phenylmethyl[1S-[[[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-1,1-dimethylethyl1-amino]carbonyl]-2-phenylethyl]carbamate,monohydrochloride ##STR47##

Compound A of Example 25 was treated with HCl by the procedure ofExample 3 to give the title compound as a white solid.

Calculated for C₃₂ H₄₁ N₄ O₅ Cl+0.5 H₂ O(MW=606.16): C, 63.41; H, 6.98;N, 9.24; Cl, 5.85. Found: C, 63.41; H, 6.98; N, 9.24; Cl, 5.85.

[α]_(D) =+72°, MeOH.

H¹ NMR (CD₃ OD)δ:1.02 (s, 3H), 1.03 (s, 3H), 2.25 (s, 6H).

Example 27 1,1-Dimethylethyl[1S-[[[1,1-dimethyl-2-[(1-oxo-3-phenyl-2S-[[(2-propenylamino)carbonyl]amino]propyl]-amino]ethyl]aminocarbonyl]-2-(4-hydroxy-2,6-dimethylphenyl)ethyl]carbamate##STR48##

The free base of the title compound of Example 11 was stirred withallylisocyanate in a mixture of benzene (25 mL) and CH₂ Cl₂ (15 mL) for18 hours at room temperature. The reaction mixture was washed with 0.5 NKHSO₄, dried over MgSO₄ and concentrated in vacuo. The residue waschromatographed to give the title compound as a white solid.

Calculated for C₃₃ H₄₇ N₅ O₆ +0.5 H₂ O (MW=618.78): C, 64.06; H, 7.82;N, 11.32. Found: C, 64.07; H, 7.70; N, 11.09

[α]_(D) =+21.2°, CHCl₃.

Example 28αS-amino-N-[1,1-dimethyl-2-[1-oxo-3-phenyl-2S-[(2-propenylamino)carbonyl]amino]propyl]amino]ethyl]-4-hydroxy-2,6-dimethylbenzenepropanamide,monohydrochloride ##STR49##

The title compound of Example 27 was treated with HCl by the method ofExample 3 to give the title compound as a white solid.

Calculated for C₂₈ H₃₉ N₅ O₄ +1.0 HCl+0.5 H₂ O (MW=555.20): C, 60.58; H,7.44; N, 12.62; Cl, 6.39. Found: C, 60.21; H, 7.44; N, 12.48; Cl, 6.66.

[α]_(D) =+85.7°, MeOH.

H¹ NMR (CD₃ OD) δ: 0.87 (s, 3H), 1.19 (s, 3H), 2.28 (s, 6H).

Example 29 Compound APhenylmethyl[1S-[[[2-[[2S-[[(1,1-dimethylethoxy)carbonyl]amino]-3-(4-hydroxy-2,3,6-trimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]amino]carbonyl]-2-phenylethyl]carbamate##STR50## Compound BPhenylmethyl[1S-[[[2-[[2R-[[(1,1-dimethylethoxy)carbonyl]amino]-03-(4-hydroxy-2,3,6-trimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]amino]carbonyl]-2-phenylethyl]carbamate##STR51##

1,2-Diamino-2-methylpropane was coupled toN-benzyloxycarbonyl-L-phenylalanine (Z-Phe) andN-Boc-DL-2,3,6-trimethyltyrosine in succession using the protocol of A.R. Jacobson et al., supra., described above in Example 9. The reactionprocedure produced two diastereoisomers which were separated bychromatography. The less polar isomer, title Compound A, and the morepolar isomer, title Compound B, were both white solids.

Compound A

Calculated for C₃₈ H₅₀ N₄ O₇ +0.125 H₂ O (MW=677.09): C, 67.41; H, 7.48;N, 8.27. Found: C, 67.27; H, 7.71; N, 8.12.

[α]_(D) =+14.6°, CHCl₃.

Compound B

Calculated for C₃₈ H₅₀ N₄ O₇ +0.25 H₂ O (MW=679.34): C, 67.19; H, 7.49;N, 8.25. Found: C, 67.09; H, 7.62; N, 8.15.

[α]_(D) =-15.4°, CHCl₃.

Example 30Phenylmethyl[1S[[[2-[[2S-amino-3-(4-hydroxy-2,3,6-trimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]amino]carbonyl]-2-phenylethyl]carbamate,hydrochloride ##STR52##

Title Compound A of Example 29 was treated with HCl by the procedure ofExample 3 to give the title compound as a white solid.

Calculated for C₃₃ H₄₂ N₄ O₅ +1.1 HCl+0.25 H₂ O (MW=619.33): C, 64.00;H, 7.10; N, 9.05; Cl, 6.30. Found: C, 63.89; H, 7.19; N, 8.76; Cl, 6.41.

[α]_(D) =+46.4°, MeOH.

H¹ NMR (CD₃ OD) δ: 0.85 (s, 3H), 1.13 (s, 3H), 2.11 (s, 3H), 2.25 (s,6H).

Example 31

Phenylmethyl[1S[[[2-[[2R-amino-3-(4-hydroxy-2,3,6-trimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]amino]carbonyl1-2-phenylethyl]carbamate,hydrochloride ##STR53##

Title Compound B of Example 29 was treated with HCl by the procedure ofExample 3 to give the title compound as a white solid.

Calculated for C₃₃ H₄₂ N₄ O₅ +1.1 HCl+0.25 H₂ O (MW=619.33): C, 64.00;H, 7.10; N, 9.05; Cl, 6.30. Found: C, 64.09; H, 7.29; N, 9.00; Cl, 6.37.

[α]_(D) =-58.7°, MeOH

H¹ NMR (CD₃ OD) δ: 0.89 (s, 3H), 1.14 (s, 3H), 2.10 (s, 3H), 2.24 (s,6H).

Example 321,1-Dimethylethyl[1S[[[1,1-dimethyl-2-[(1-oxo-3-phenyl-2S-[[[(phenylmethyl)amino]carbonyl]aminopropyl]amino]ethyl]amino]carbonyl]-2-(4-hydroxy-2,6-dimethylphenyl)ethyl]carbamate##STR54##

The free base of the title compound of Example 11 was treated withbenzylisocyanate by the method of Example 27 to give the title compoundas a white solid.

Calculated for C₃₇ H₄₉ N₅ O₆ (MW=659.86): C, 67.35; H, 7.49; N, 10.61.Found: C, 67.05; H, 7.58; N, 10.57.

[α]_(D) =-6.3°, CHCl₃.

Example 33αS-amino-N-[1,1-dimethyl-2-[[1-oxo-3-phenyl-2S-[[[(phenylmethyl)amino]carbonyl]amino]propyl]-amino]ethyl]-4-hydroxy-2,6-dimethylbenzeneprooanamide,hydrochloride ##STR55##

The title compound of Example 32 was treated with HCl by the procedureof Example 3 to give the title compound as a white solid.

Calculated for C₃₂ H₄₁ N₅ O₄ +1.1 HCl+0.5 H₂ O (MW=608.83): C, 63.13; H,7 14; N, 11.50; Cl, 6.41. Found: C, 63.22; H, 7.14; N, 11.36; Cl, 6.40.

[α]_(D) =+72.3°, MeOH.

H¹ NMR (CD₃ OD) δ: 0.85 (s, 3H), 1.20 (s, 3H), 2.26 (s, 6H).

Example 34Ethyl[[[[1S[[[2-[[2S-[[(1,1-dimethylethoxy)carbonyl]amino]-3-(4-hydroxy-2,6-dimethylphenyl)-l-oxopropyl]amino]-2-methylpropyl]amino]carbonyl]-2-phenylethyl]amino]carbonyl]amino]acetate##STR56##

The free base of the title compound of Example 11 was treated with ethylisocyanatoacetate by the method of Example 27 to give the title compoundas a white solid.

Calculated for C₃₄ H₄₈ N₅ O₈ +0.2 H₂ O (MW=658.39): C, 62.03; H, 7.41;N, 10.64. C, 61.67; H, 7.46; N, 10.48.

[α]_(D) =-8.5°, CHCl₃.

Example 35αS-amino-N-[1,1-dimethyl-2-[[1-oxo-3-phenyl-2S-[[[(phenylmethyl)amino]carbonyl]amino]propyl]amino]ethyl]-4-hydroxy-2,6-dimethylbenzeneprooanamide,hydrochloride ##STR57##

The title compound of Example 34 was treated with HCl by the procedureof Example 3 to give the title compound as a white solid.

Calculated for C₂₉ H₄₀ N₅ O₆ +1.1 HCl+0.4 H₂ O (MW=601.98): C, 57.86; H,7.02; N, 11.63; Cl, 6.48 Found: C, 57.86; H, 7.12; N, 11.44; Cl, 6.31.

[α]_(D) =+79.4°, MeOH.

H¹ NMR (CD₃ OD) δ: 0.87 (s, 3H), 1.18 (s, 3H), 2.28 (s, 6H).

Example 36 1,1-Dimethylethyl[1S[[[1,1-dimethyl-2-[[(1-oxo-3-phenyl-2S-[(methylamino)carbonyl]amino]propyl]amino]ethyl]amino]carbonyl]-2-(4-hydroxy-2,6-dimethylphenyl)ethyl]carbamate##STR58##

The free base of the title compound of Example 11 was treated withmethyl isocyanate by the method of Example 27 to give the title compoundas a white solid.

Calculated for C₃₁ H₄₈ N₅ O₆ +0.9 H₂ O (MW=519.26): C, 62.06; H, 7 86;N, 11.67. Found: C, 61.96; H, 7.65; N, 11.52.

[α]_(D) =+4.5°, CHCl₃.

Example 37αS-amino-N-1,1-dimethyl-2-[2S-[[(methylamino)carbonyl]amino]-1-oxo-3-phenylpropyl]amino]ethyl]-4-hydroxy-2,6-dimethylbenzeneoropanamide,monohydrochloride ##STR59##

The title compound of Example 36 was treated with HCl by the procedureof Example 3 to give the title compound as a white solid.

Calculated for C₂₆ H₃₇ N₅ O₄ +1.0 HCl+0.75 H₂ O (MW=533.59): C, 58.53;H, 7.46; N, 13.13; Cl, 6.64. Found: C, 58.61; H, 7.54; N, 12.64; Cl,6.30.

[α]_(D) =+87.0°, MeOH.

H¹ NMR (CD₃ OD) δ: 0.87 (s, 3H), 1.18 (s, 3H), 2.28 (s, 6H).

Example 381,1-Dimethylethyl[1S[[[2-[2S-(acetylamino)-1-oxo-3-phenylpropyl]amino]-2-methylpropyl]amino]carbonyl]-2-(4-hydroxy-2,6-dimethylphenyl)ethyl]carbamate ##STR60##

Removal of the benzyloxycarbonyl (Z) group from title Compound A ofExample 25 was accomplished by the method of Example 4 to give a freebase. This free base was then converted to the white solid titlecompound by the process of Example 13, with the exception that aceticanhydride was used in place of trifluoroacetic anhydride.

Calculated for C₃₁ H₄₄ N₅ O₆ +0.6 H₂ O (MW=579.52): C, 64.25; H, 7.86;N, 9.67. Found: C, 64.02; H, 7.74; N, 9.48.

[α]_(D) =+45.8°, CHCl₃.

Example 39αS-(Acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-1,1-dimethylethyl]-benzenepropanamide,monohydrochloride ##STR61##

The title compound of Example 38 was treated with HCl by the procedureof Example 3 to give the title compound as a white solid.

Calculated for C₂₆ H₃₆ N₄ O₄ +1.0 HCl+0.75 H₂ O (MW=518.57): C, 61.83;H, 7.38; N, 11.09; Cl, 7.02. Found: C, 60.22; H, 7 42; N, 10.80; Cl,6.84.

[α]_(D) =+102.9°, MeOH.

H¹ NMR (CD₃ OD) δ: 1.01 (s, 3H), 1.04 (s, 3H), 2.25 (s, 6H).

Example 401,1-Dimethylethyl[1R-[[[2-[[2S-(acetylamino)-1-oxo-3-phenylpropyl]amino]-1,1-dimethylethyl]amino]carbonyl]2-(4-hydroxy-2,3,6-trimethylphenyl)ethyl]carbamate ##STR62##

Removal of the Z group from title Compound A of Example 29 wasaccomplished by the method of Example 4 to give a free base. This freebase was then converted to the white solid title compound by the processof Example 13, with the exception that acetic anhydride was used inplace of trifluoroacetic anhydride.

Calculated for C₃₂ H₄₆ N₄ O₆ +0.25 H₂ O (MW=587.25): C, 65.45; H, 7.98;N, 9.54. Found: C, 65.46; H, 8.09; N, 9.12.

[α]_(D) =-40.0°, CHCl₃.

Example 41αS-(acetylamino)-N-[2-[[2R-amino-3-(4-hydroxy-2,3,6-trimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]benzenepropanamide, monohydrochloride##STR63##

The title compound of Example 40 was treated with HCl by the procedureof Example 3 to generate the title compound as a white solid.

Calculated for C₂₇ H₃₈ N₄ O₄ +1.0 HCl+0.5 H₂ O (MW=528.10): C, 62.48; H,7.57; N, 10.79; Cl, 6.83. Found: C, 61.41; H, 7.63; N, 10.61; Cl, 6.71

[α]_(D) =-49.0°, MeOH.

H¹ NMR (CD₃ OD) δ: 0.90 (s, 3H), 1.14 (s, 3H), 1.91 (s, 3H), 2.23 (s,6H).

Example 421,1-Dimethylethyl[(1R-methyl-2-[(phenylmethyl)amino]ethyl]carbamate##STR64##

t-Butyloxycarbonyl-D-alanine (Boc-D-Ala) was coupled to benzylamineusing the mixed anhydride method described in Example 2 to give thewhite solid Boc-D-Ala-NH2-CH₂ -phenyl, which was used without furtherpurification. To a stirred solution of 10 g of this material in 75 mL ofTHF at -20° C. was added 72 mL of a 1 M THF solution of borane in drops.The mixture was allowed to stir for 6.5 hours at -20° C. To this mixturewas added 40 mL of MeOH in drops. The mixture was concentrated in vacuo.The residue was treated with 50 mL of MeOH and the volatiles wereremoved in vacuo. This process of addition of MeOH and concentration wasrepeated three times. The residue was suspended in 400 mL of water andacidified to pH=2 with concentrated hydrochloric acid. The solution wasextracted with ether. The organic phase was discarded. The aqueous phasewas basified with saturated aqueous K₂ CO₃ and extracted with ether. Theether extract was dried over MgSO₄ and concentrated in vacuo to leave1.04 g of the title compound, which was used in Example 53 withoutfurther purification.

Example 43 1,1-Dimethylethyl(2-amino-1R-methylethyl)carbamate ##STR65##

The title compound of Example 42 (0.912 g) was hydrogenated in MeOH (25mL) with 10% Pd on carbon under 60 psi hydrogen pressure for 22 hours.The reaction was worked up as described in Example 4 to give the titlecompound (0.595 g) as a white solid.

Example 441,1-Dimethylethyl[(1R-methyl-2-[(phenylmethyl)amino]ethyl]carbamate##STR66##

The title compound of Example 43 was coupled to Z-Phe by the method ofExample 2 to give the title compound as a white solid.

Example 45Phenylmethyl[1S-[[[2R-[[2S-[[(1,1-dimethylethoxy)carbonyl]amino]-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]propyl]carbonyl-2-phenylethyl]carbamate##STR67##

The title compound of Example 44 was treated with HCl by the method ofExample 3. The resulting amine hydrochloride salt was treated with amolar equivalent of NMM and then coupled to Boc-DMT using the mixedanhydride coupling procedure of Example 2 to give the title compound aswhite solid.

Calculated for C₃₆ H₄₆ N₄ O₇ +0.25 H₂ O (MW=651.29): C, 66.39; H, 7.20;N, 8.60. Found: C, 66.33; H, 7.23; N, 8.37.

[α]_(D) =+12.8°, CHCl₃.

Example 46Phenylmethyl[1S[[[2R-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]propylamino]carbonyl]-2-phenylethyllcarbamate,hydrochloride ##STR68##

The title compound of Example 45 was treated with HCl by the method ofExample 3 to give the title compound as a white solid.

Calculated for C₃₁ H₃₈ N₄ O₅ +0.9 HCl+0.5 H₂ O (MW=588.49): C, 63.85;H,6.74; N, 9.61; Cl, 6.08. Found: C, 63.27; H, 6.83; N, 9.54; Cl, 5.42.

[α]_(D) =+45.9°, MeOH.

H¹ NMR (CD₃ OD) δ:0.72 (d, 3H), 2.23 (s, 6H).

Example 47αS-(Acetylamino)-N-[2-[[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]-benzenepropanamide,monohydrochloride ##STR69##

To CH₂ Cl₂ (70 mL) at 0° C. was added 3.9 g of Boc-DMT, 3.5 g ofN-acetyl-phenylalanine-NHCHC(CH₃)₂ NH₂ of A. R. Jacobson et al., supra.,and 1.7 g of hydroxybenzotriazole (HOBT). After stirring for 5 minutes,2.86 g of dicyclohexylcarbodiimide (DCC) was added. The reaction mixturewas allowed to warm to room temperature overnight with stirring. Afterfiltration, the mother liquor was washed with two 100 mL portions ofhalf-saturated Na₂ CO₃ and evaporated to dryness in vacuo. The crudeproduct obtained Was treated with a 1:1 mixture of 15 mL of CH₂ Cl₂ and7 N HCl in dioxane for 5 minutes at room temperature to remove the Bocprotecting group. The volatiles were removed and the residue waspurified by chromatography over silica gel using a mobile phase of CHCl₃/MeOH (8:1) containing 1% aqueous NH₃ to give the free base of the titlecompound. Treatment of an ethanol solution of this free base with dryHCl gas and removing the volatiles in vacuo gave the title compound as awhite solid.

H¹ NMR (D₂ O) δ:0.90 (s, 3 H), 1.0 (s, 3 H), 1.98 (s, 3 H), 2.18 (s, 3H), 2.92-3.25 (complex m, 6 H), 3.89 (dd, J=10, 7 Hz, 1 H), 4.43 (t,J=7.5, 1 H), 6.68 (s, 2 H), 7.22-7.43 (complex m, 5 H).

HPLC (Zorbax-Rx-C-8, 17/83 acetonitrile/TEAP (triethylamine-phosphatebuffer, pH=3))=15.3.

[α]_(D) =+80.6 (MeOH).

Example 48αS-(Acetylamino)-N-[(2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]aminoethyl]benzenepropanamide,hydrochloride ##STR70##

To 100 mL of DMF was added N-acetyl-phenylalanine [N-Ac-PheOH (Aldrich,Milwaukee, Wis.), 5 g], 1.61 mL of ethylenediamine, 4.6 g ofpara-toluenesulfonic acid. H₂ O and 3.3 g of HOBT. After allowing themixture to stir for 5 minutes, 5.1 g of DCC was added and the reactionmixture was stirred for 16 hours. The solvent was removed in vacuo and500 mL of CHCl₃ was added. The mixture was filtered and the filtrate waswashed with two 200-mL portions of half-saturated aqueous Na₂ CO₃. Theorganic extract was concentrated in vacuo. The residue waschromatographed on silica gel using EtOAc/MeOH (4:1 ) containing 1%aqueous NH₃ to give 1.5 g of white solid, H₂ N(CH₂)₂NH-phenylalanine-NH-acetyl.

To a solution of 1.723 g of Boc-DMT in 50 mL of THF at -10° C. was added0.615 mL of N-methylmorpholine (NMM) followed by 0.725 mL ofisobutylchloroformate (IBCF). The mixture was stirred for 30 minutes. Tothis mixture was added 1.342 g of H₂ N(CH₂)₂ NH-phenylalanine-NH-acetylin 20 mL of DMF. The mixture was stirred and allowed to warm to roomtemperature over 16 hours. The mixture was concentrated and the residuewas taken up in EtOAc and water. The organic phase was washed with 0.5 NKHSO₄, saturated NaHCO₃, dried over MgSO₄ and concentrated in vacuo. Theresidue was chromatographed on silica using EtOAc containing 1% MeOH.The white solid obtained was taken up in 10 mL of CH₂ Cl₂ and 7 N HCl indioxane (1:1) and allowed to stand at room temperature for 5 minutes.The volatiles were removed and the residue was chromatographed oversilica gel using CHCl₃ /MeOH (8:1) containing 1% aqueous NH₃ to give 1 gof the free base of the title compound. The title compound was obtainedas a white solid salt by dissolving the free base in EtOH containing dryHCl and azeotropic drying.

H¹ NMR (DMSO-d₆) δ: 1.76 (s, 3 H), 2.18 (s, 6 H), 2.70-3.08 (complex m,8 H), 3.63 (m, 1 H), 4.36 (m, 1 H), 6.43 (s, 2 H), 7.16-7.29 (complex m, 5 H), 8.09 (bs, 2 H), 8.21 (d, J=8 Hz, 1 H), 8.56 (bs, 3 H), 9.12(very bs, 1 H).

HPLC (Zorbax-Rx-C-8, 30/70 to 90/10 for 20 minutes, 90/10 for 5 minutes,methanol/TEAP)=8.97

[α]_(D) =+109.9 (MeOH)

Example 49 N-Acetyl-2,6-dimethyl-L-phenylalanine, methyl ester ##STR71##

A mixture of 3,5-dimethyl-4-iodophenyl acetate (175 g, 603 mmol), methyl2-acetamidoacrylate (90.6 g, 633 mmol), tri-o-tolylphosphine (9.70 g, 319 mmol), Et₃ N (167 mL, 121 g, 1.20 mol) and palladium(II) acetate (2.51g, 11.2 mmol) in CH₃ CN (850 mL) was refluxed for 22 hours. The mixturewas cooled to room temperature and filtered through a bed of Super-Cel.The solvent was removed in vacuo and the residue was diluted with water(1 L). The aqueous phase was extracted three times with EtOAc (4 Ltotal). The organic phase was washed with a saturated NaCl solution (3 Ltotal), treated with Darco®, and dried over anhydrous Na₂ SO₄. Themixture was filtered and concentrated in vacuo. Recrystallization from25% EtOAc/75% hexane (˜3 L total) afforded methyl 2-(acetylamino)-3-[4-(acetyloxy)-2,6-dimethylphenyl]-2Z-propanoate (156 g, 84.7 %).

An N₂ -purged reaction vessel was charged with a slurry of Rhodium1,5-cyclooctadiene[R,R]-1,2-ethanediylbis[[o-methoxyphenyl]phenylphosphine]tetrafluoroborate (35.5 g, 47.0mmol, methyl2-(acetylamino)-3-[4-(acetyloxy)-2,6-dimethylphenyl]-2Z-propanoate (1.43kg, 4.68 mol) and EtOAc (7.2 L) using additional EtOAc (7.2 L) as arinse. The reaction mixture was heated to 60° C. and repeatedlypressurized to 60 psig with N2 and vented to 10 psig until the ventstream contained <5 ppm of O₂, as measured by a Teledyne O₂ analyzer.The reaction vessel was then purged five times by pressurizing to 60psig with H₂ and venting to 10 psig. The vent stream was again checkedto ensure that it contained <5 ppm of O₂. The reaction mixture waspressurized to 60 psig with H₂ and stirred vigorously for 24 hours, atwhich time TLC analysis (60 % EtOAc/40% toluene) indicated the completedisappearance of starting material. The reaction mixture was cooled to25° C., vented with N₂, and added to a second reaction vessel containingFlorisil® (2.15 kg) using EtOAc (4 L) as a rinse. The mixture wasfiltered through a bed of Super-Cel, and the bed was washed with EtOAc(4.3 L). Approximately 3/4 of the solvent was removed by vacuumdistillation at 40° C. The resulting slurry was cooled to 25° C. anddiluted with hexane (21.5 L). The product was collected by filtration,washed with hexane (5.7 L), and dried to giveN-acetyl-2,6-dimethyl-L-tyrosine methyl ester (1.25 kg, 86.7%) as acrystalline solid, DSC 112.25° C. (max endotherm), 200 MHz ¹ H (CDCl₃) δ1.97 (s, 3H), 2.27 (s, 3H), 2.33 (s, 6H), 3.03 (dd, J=8.5 Hz, J=14 Hz,1H), 3.12 (dd, J=7 5 Hz, J=14 Hz, 1H), 3.60 (s, 3H), 4.79 (q, J=8, 1H),6.11 (br d, J=8 Hz, 1H), 6.75 (s, 2H); Analysis calculated for C₁₆ H₂₁NO₅ :C, 62.53; H, 6.89; N, 4.56; Found C, 62.42; H, 7.11; N, 4.53.

A mixture of 10 g of N-acetyl-2,6-dimethyl-L-tyrosine methyl ester and 5g of NaHCO₃ in 100 mL of MeOH and 10 mL of water was stirred at roomtemperature for 16 hours. The mixture was acidified with 1 N HCl andextracted with ether. The ether extract was washed with water, driedover MgSO₄ and concentrated in vacuo to leave 7 g ofN-acetyl-2,6-dimethyltyrosine methyl ester as a white solid. 6.87 g ofthis material was stirred with 4.75 g of 5-chloro-1-phenyl-1H-tetrazoleand 7.2 g of K₂ CO₃ in 130 mL of DMF for 16 hours. The mixture was addedto water and extracted with EtOAc. The organic extract was washed fourtimes with water, dried over MgSO₄ and concentrated. The residue wastriturated with ether and filtered to give 7.89 g of a solid [H¹ NMR(CDCl₃) δ: 2.00 (s, 3 H), 2.20 (s, 6 H), 3.04-3.18 (complex, 2 H), 3.65(s, 3 H), 4.83 (q, J=8 Hz, 1 H), 6.25 (d, J=8 Hz, 1 H), 7.06 (s, 2 H),7.49-7.63 (complex, 3 H), 7.80 (d, J=8 Hz, 2 H)]. This material in 100mL of HOAc was shaken with 10% Pd on carbon under 60 psi of hydrogenpressure at 40° C. for 24 hours. The mixture was filtered and thefiltrate was concentrated in vacuo. The residue was extracted with EtOAcand water. The organic phase was washed with saturated NaHCO₃, water,dried over MgSO₄ and concentrated in vacuo. The residue was trituratedwith ether and filtered to give 4.48 g of the title compound as a whitesolid.

H¹ NMR (CDCl₃) δ: 2.00 (s, 3 H), 2.37 (s, 6 H), 3.13 (d, J=8 Hz, 2 H),3.63 (s, 3 H), 4.87 (q, J=8 Hz, 1 H), 6.37 (d, J=8 Hz, 1 H), 7.00-7.10(complex, 3 H).

[α]_(D) =+14.5 (MeOH).

Example 50 N-Acetyl-2,6-dimethyl-L-phenylalanine ##STR72##

The title compound of Example 49 (4.44 g) was stirred in 19 mL of THFand 18.8 mL of 1 M lithium hydroxide for 15 minutes. The volatiles wereremoved in vacuo and diluted with water. Acidification with 0.5 N KHSO₄precipitated a white solid which was filtered and dried in vacuo at 56°C. for 16 hours to give 3.9 g of the title compound as a white solid.

H¹ NMR (CDCl₃ --CD₃ OD) δ: 1.93 (s, 3H), 2.37 (s, 6 H), 3.06 (dd, J=14,8 Hz, 1 H), 3.21 (dd, J=14, 7 Hz, 1 H), 4.74 (dd, J=8, 7 Hz, 1 H),6.97-7.06 (complex, 5 H).

[α]_(D) =+29.3 (MeOH).

Example 51αS-(Acetylamino)-N-[2-[[2S-amino-3-(4-hydroxyphenyl)-1-oxopropyl]amino]ethyl]-2,6-dimethylbenzenepropanamide.hydrochloride ##STR73##

The title compound was obtained as a white solid by the method ofExample 48 using the title compound of Example 50 and Boc-tyrosine inplace of N-Ac-PheOH and Boc-DMT respectively.

H¹ NMR (DMSO-d₆) δ: 1.80 (s, 3 H), 2.29 (s, 6 H), 2.78-3.07 (complex, 8H), 3.82 (m, 1 H), 4.43 (q, J=8 Hz, 1 H), 6.71 (d, J=8 Hz, 2 H),6.89-6.98 (complex, 3 H), 7.02 (d, J=8 Hz, 2 H), 7.91 (t, J=5 Hz, 1 H),8.24 (bs, 3 H), 8.32 (d, J=8 Hz, 1 H), 8.48 (m, 1 H), 9.37 (Very bs, 1H).

HPLC (Zorbax-Rx-C-8, 15/85, MeOH/TEAP)=10.90.

[α]_(D) =+107.5 (c=2, MeOH).

Example 52αS-(Acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]ethyl]-2,6-dimethylbenzeneoropanamide,hydrochloride ##STR74##

The title compound was obtained as a white solid by the method ofExample 48 using the title compound of Example 50 in place ofN-Ac-PheOH.

H¹ NMR (DMSO-d₆) δ: 1.80 (s, 3 H), 2.16 (s, 6 H), 2.28 (s, 6 H),2.53-3.04 (complex, 8 H), 3.59 (m, 1 H), 4.39 (q, J=7.5 Hz, 1H), 6.43(s, 2 H), 6.90-7.01 (m, 3 H), 7.77-7.84 (m, 1 H), 7.99 (t, J=5 Hz, 1 H),8.26 (d, J=8 Hz, 1 H), 8.30 (bs, 1 H), 9.14 (very bs, 1 H).

HPLC (Zorbax-Rx-C-8, 30/70 to 90/10 for 20 minutes, 90/10 for 5 minutes,methanol/TEAP)=11.86.

[α]_(D) =+134.9 (MeOH).

Example 531-[2S-Amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]-4-(phenylmethyl)piperazine,dihydrochloride ##STR75##

To a solution of 2 g of Boc-DMT in 25 mL of THF at -23° C. was added0.7I mL of NMM followed by 0.84 mL of IBCF. The mixture was stirred for30 minutes. To this was added a solution of 1.13 mL ofN-benzylpiperazine in 5 mL of THF. The mixture was stirred for 16 hoursand concentrated in vacuo. The residue was taken up in EtOAc and water.The organic phase was washed with saturated Na₂ CO₃, dried over MgSO₄and concentrated in vacuo. The residue was chromatographed on silica gelusing 60% EtOAc in hexane containing 2% triethylamine to give 3 g of awhite solid (Compound A, the Boc precursor of the title compound). 0.2 gof this solid was dissolved in a mixture of 5 mL each of CH₂ Cl₂ and 7 NHCl in dioxane. The solution was allowed to stand at room temperaturefor 15 minutes. The volatiles were removed in vacuo to give the titlecompound as a white solid.

HPLC (Zorbax-Rx-C-8, 30/70 to 90/10 for 20 minutes, 90/10 for 5 minutes,methanol/TEAP)=11.21.

[α]_(D) =+48.2 (MeOH).

Example 54N-[1S-[[4-[2-S-Amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]-1-piperazinyl]carbonyl]-2-phenylethyl]acetamide,monohydrochloride ##STR76##

2.4 g of the Boc precursor of the title compound of Example 53 wasshaken in 100 mL of EtOH with 5% Pd on carbon under 60 psi of hydrogenfor 8 hours. The mixture was filtered to remove the catalyst and thefiltrate was concentrated to give 1.3 g of white solid. This materialwas coupled to N-acetyl-L-phenylalanine using the mixed anhydridecoupling procedure described in the preparation of the title compound ofExample 53. The crude product was treated with acid to remove the Bocprotecting group as described in the preparation of the title compoundof Example 47. The crude amine hydrochloride obtained waschromatographed over silica gel using EtOAc/triethylamine/MeOH (98/2/5)to give 0.2 g of the free amine corresponding to the title compoundwhich was converted to the hydrochloride salt by the method describedfor the title compound of Example 47.

HPLC (Zorbax-Rx-C-8, 30/70 to 90/10 for 20 minutes, 90/10 for 5 minutes,methanol/TEAP)=9.70.

[α]_(D) =+53.5 (MeOH).

Example 551,1-Dimethylethyl[1S-[[[1-[2S-(acetylamino)-1-oxo-3-phenylpropyl]-3-pyrrolidinyl]amino]carbonyl]-2-(4-hydroxy-2,6-dimethylphenyl)ethyl]carbamate ##STR77##

1-Benzyl-3-amino-pyrrolidine was used in the place of 1-benzylpiperazineint he mixed anhydride procedure of Example 53 to give the titlecompound as a white solid.

Example 56N-1-[2S-(Acetylamino)-1-oxo-3-phenylpropyl]-3-pyrrolidinyl]-αS-amino-4-hydroxy-2,6-dimethylbenzenepropanamide,monohydrochloride ##STR78##

The title compound of Example 55 was subjected to hydrogenation and theresulting product was reacted with N-Ac-L-PheOH as described in Example54. Subsequent removal of the Boc protecting group as described inExample 54 gave the title compound as a white solid.

HPLC (VYOAC-C-18, 90/10 acetonitrile/TEAP)=18.49.

[α]_(D) =+116.8 (MeOH).

Example 57αS-(Acetylamino)-N-[3[[[2S-amino-3-[4-hydroxy-2,6-dimethylphenyl]-1-oxopropylamino]phenyl]benzenepropanamide,hydrochloride ##STR79##

To a solution of 2.06 g of Boc-DMT in 50 mL of THF at -23° C. was added0.73 mL of NMM followed by 0.86 mL of IBCF. The mixture was stirred for30 minutes and treated with 0.92 g of m-nitroaniline in 10 mL of THF.The resulting mixture was stirred for four days at room temperature. Thevolatiles were removed in vacuo. The reaction mixture was worked up asdescribed in Example 53. The crude product obtained was triturated withether to give 2.7 g of a solid. 1.2 g of this solid was hydrogenated inMeOH with 4% Pd on carbon under 5 psi of hydrogen pressure for 16 hours.The mixture was filtered to remove the catalyst and the filtrate wasconcentrated in vacuo to leave 1 g of a solid. This material was treatedwith the mixed anhydride obtained from 0.576 g of N-Ac-L-PheOH, 0.28 mLof NMM and 0.33 mL of IBCF in 25 mL of THF using the procedure describedin Example 48. The product obtained was treated with acid to remove theBOC protecting group as described for Example 47. After the removal ofthe volatiles, the resulting material was chromatographed over silicagel using EtOAC/MeOH/triethyl amine, 50:2:1, to give the free base ofthe title compound. This material was taken up in acetic acid and dryHCl (gas) was bubbled for a few minutes. The volatiles were removed andthe residue was dried in vacuo at 60° C. for 16 hours to give the titlecompound as a white solid.

H¹ NMR (DMSO-d₆) δ: 1.80(s, 3 H), 2.20(s, 6 H), 2.83 (dd, J=14, 10 Hz, 1H), 2.96-3.17(complex, 3 H), 3.93 (m, 1 H), 4.53 (m, 1 H), 6.34 (s, 2H), 7.17-7.33 (9 H), 7.74 (bs, 1 H), 8.32 (d, J=8 Hz, 1 H), 8.63 (bs, 3H), 9.09 (bs, 1 H), 9.98 (s, 1 H), 10.2 (s, 1 H).

HPLC (Zorbax-Rx-C-8, 30/70 to 90/10 for 20 minutes, 90/10 for 5 minutes,methanol/TEAP)=11.72.

[α]_(D) =+187.7 (MeOH).

Example 581,1-Dimethylethyl-[2-[[1,1-dimethyl-2-[[1-oxo-3-phenyl-2S-[[[(phenylsulfonyl)amino]carbonyl]amino]propyl]amino]ethylamino]-1S-[(4-hydroxy-2,6-dimethylphenyl)methyl]-2-oxoethyl]-carbamate##STR80##

The free base of the title compound of Example 11 was treated withbenzenesulfonyl isocyanate by the procedure described in Example 27 togive the title compound as a white solid.

Example 59S-amino-N-[1,1-dimethyl-2-[[1-oxo-3-phenyl-2S-[[[(phenylsulfonyl)amino]carbonyl]amino]propyl]amino]ethyl]-4-hydroxy-2,6-dimethylbenzeneoropanamide,monohydrochloride ##STR81##

The title compound of Example 58 was treated with HCl by the proceduredescribed in Example 3 to give the title compound as a white solid.

Calculated for C₃₁ H₃₉ N₅ O₆ S+1.1 HCl+1.25 H₂ O; C, 55.38; H, 6.37; N,10.42; Cl,5.80. Found: C, 55.45; H, 6.23; N, 9.88; Cl, 5.81.

[α]_(D) =+45.5°, MeOH.

H¹ NMR (CD₃₀ D) d: 0.9 (s, 3H), 1.2 (s, 3H), 2.3 (s, 6H).

Example 60 Writhing Assay

The "Writhing Assay" is one of the most widely-used experimentalprocedures for measuring the analgesic activity of different narcoticand nonnarcotic analgesic agents, and involves the continuous,chemically-induced pain of visceral origin to an animal, such as a mouseor rat. [Gyires et al., Arch. int. Pharmacodyn, 267, 131-140 (1984); C.Vander Wende et al., Fed. Proc., 15, 494 (1956); Koster et al., Fed.Proc., 18, 412 (1959); and Witken et al., J. Pharmacol. Exp. Ther., 133,400-408 (1961).] Chemicals which may be used to induce this pain includephenylbenzoquinone (PBQ) and acetic acid. As a result of the chemicalirritation to the animal, a characteristic stretching and writhing ofthe animal (dorsiflexion of the animal's back, extension of itshindlimbs and the strong contraction of its abdominal musculature) willgenerally occur. The intensity of this pain reaction is determined bythe number of writhes exhibited by the animal during a given period oftime. Drugs which reduce the number of writhes of the animal appear torestore the normal nociceptive threshold of the animal.

Compounds within the present invention exhibit analgesic activity inmice, as shown by the results of the Writhing Assay presented in Table Ibelow.

This assay was conducted generally in the manner described by R. I.Taber, "Predictive Value of Analgesic Assays in Mice and Rats," Advancesin Biochemical Phychopharmacology, 8, 191 (1974).

Two hundred CD Charles River mice, weighing 20 to 30 grams, were used inthis assay.

Twenty-five minutes after subcutaneous administration, and fifteenminutes after oral administration, to the mice of 10 mg per kilogram(mpk) of body weight of either a tyrosyl diamide compound of theinvention (hereinafter "test compound"), or of the Jacobson Compound,0.1 mL per 10 g of body weight of a 0.025% w/v solution ofphenylbenzoquinone (PBQ) was injected intraperitoneally into each mouse.Some mice were given saline in place of a test compound, or of theJacobson Compound, and were used as a control group.

Five minutes later, each mouse was individually placed into a glassbeaker for observation, and the number of writhes occurring during thefollowing ten-minute period was counted.

A compound was considered to be "active" (to have produced analgesia ina mouse) if, after the administration of 10 mg per kilogram (mpk) ofbody weight of the compound to the mouse, the number of writhes elicitedby a mouse injected with PBQ was equal to, or less than, one-half themedian number of writhes recorded for the saline-treated control groupof mice that day, as described by R. I. Taber, supra.

The standard initial screening dose of a test compound employed in thisassay was 10 mpk per gram of body weight for both routes ofadministration. If this initial screening dose of the compound producedanalgesia in seven of ten mice, then the effect of additional doses ofthe compound on the writhing response was evaluated, and then the ED₅₀value (that dose of a compound which produced analgesia in 50% of themice to which the compound was administered) was calculated. A maximumlikelihood function was used to determine the ED₅₀ value. (The slopes ofthe dose-response curves for the compounds analyzed were compared asdescribed by Tallarida and Murray, Manual of Pharmacologic Calculations,Page 1 (Springer Verlag, N.Y., 1981)).

The results for the compounds analyzed in this assay, and discussed inthe examples which correspond thereto, are presented in Table I below,and are expressed in terms of the ED₅₀ value. All of the compounds ofthe present invention tested in this assay were found to be active inall ten of the mice to which the compound was administered whenadministered subcutaneously at a dose of 10 mpk.

As Table I shows, the tyrosyl diamide compound of the invention shownand synthesized in Example 47 was determined to be the most potentcompound of the invention tested in the Writhing Assay, and is the mostpreferred compound of the invention. As Table I also shows, the compoundof the invention shown and synthesized in Example 47 was surprisinglyand unexpectedly found to be eight times more potent than the JacobsonCompound when administered to the mice subcutaneously, and seven timesmore potent than the Jacobson Compound when administered to the miceorally.

                  TABLE I                                                         ______________________________________                                        Data Generated from the Writhing Assay                                                         Subcutaneous                                                                             Oral                                              Compound         (S.C.)     (p.o.)                                            Tested           ED.sub.50  ED.sub.50                                         ______________________________________                                        Example No. 47     0.2      0.6                                               Example No. 10   5          NT                                                Example No. 16   5          NT                                                Example No. 37   5          NT                                                Example No. 52   5          NT                                                Example No. 18   5          NT                                                Jacobson Compound                                                                                1.6      4.1                                               ______________________________________                                         NT = Not Tested                                                          

Example 61 Tail Flick and Hot Plate Assays

The "Tail Flick Assay" and the "Hot Plate Assay" (also known as the"Hind Paw Lick Assay") use thermal pain of transient duration, and aretests in which the pain threshold of the mice or rats being analyzed hasnot been altered. They are useful for evaluating the ability of acompound or drug to increase the animal's pain threshold (i.e. prolongresponse latencies), rather than to restore normal thresholds.

The heat-induced response to the Tail Flick Assay is a reflex reactionmediated at the level of the spinal cord. The heat-induced response tothe Hot Plate Assay, however, is a more complex behavior requiringintegration at higher centers in the brain.

When used together, the Tail Flick Assay and Hot Plate Assay provide twodifferent methods of concurrently measuring analgesia in an animal.Compounds which are active in one of the assays may not be active in theother assay.

Opiate compounds having clinical efficacy as analgesics generallyincrease tail flick and/or hot plate latencies. Thus, morphine andcodeine are generally determined to be active in both of these tests. Incontrast, aspirin and Zomax, which are Non-Steroidal AntiinflammatoryDrugs (NSAIDs), show little activity in either of these tests. However,these tests are not sufficiently sensitive, or of the appropriatedesign, to demonstrate the analgesic activity of NSAIDs.

The Tail Flick Assay and the Hot Plate Assay were performed generally inthe manner described by G. Woolfe et al., "The Evaluation of theAnalgesic Action of Pethidine Hydrochloride (Demerol)," J. Pharmacol.Exp. Ther., 80, 300, (1944), F. D'Amour et al., "A Method forDetermining Loss of Pain Sensation," J. Pharmacol. Exp. Ther., 72, 74,300-307 (1941), and E. Drower et al., "The Antinociceptive Effects ofProstaglandin Antagonists in the Rat," European Journal of Pharmacology,133, 249-256 (1987).

Male Charles River albino mice weighing 20 to 30 g were employed inthese assays.

Tail flick response latencies (defined as the time that elapsed betweenthe onset of a high intensity beam of light and the reflex removal ofthe mouse's tail) and hot plate response latencies (defined as the timethat elapsed between the placement of a mouse on a 55 degrees Celsiussurface and a lick of the hind paw) were separately, but consecutively,measured before (baseline) and again at fixed intervals aftersubcutaneous administration of the Test Tyrosyl Diamide Compound, orafter the administration of saline (controls). The cut-off latenciesestablished to prevent tissue damage in the mice are 12 seconds in theTail Flick Assay, and 40 seconds in the Hot Plate Assay. Thesignificance of any increase in tail flick response latency or hot plateresponse latency is determined using analyses of variance.

One way analyses of variance were used to determine the significance ofthe effect of the Test Tyrosyl Diamide Compound on response latencies.For these assays, the ED₅₀ value was defined as the dose of the compoundwhich produced one half the maximum possible increase in latency (i.e.,to 7.5 seconds in the Tail Flick Assay, and to 25 seconds in the HotPlate Assay). Calculations of ED₅₀ values were based upon a leastsquared linear regression equation computed for the data at a time ofpeak effect, as described by D'Amour and Woolfe, supra.

"Activity" or "Inactivity" was determined at a particular concentrationof the compound by a significant increase in tail flick or hot platelatencies above normal latencies.

The data resulting from the Tail Flick Assay and the Hot Plate Assay forthe only compound tested in these assays, the compound shown anddescribed in Example No. 47, are presented in Tables II and III below,respectively. The numbers in the tables are calculated ED₅₀ values.

                  TABLE II                                                        ______________________________________                                        Data Generated from the Tail Flick Assay                                      Compound                                                                      Tested         Subcutaneous                                                   ______________________________________                                        Example No. 47 1.9                                                            ______________________________________                                    

                  TABLE III                                                       ______________________________________                                        Data Generated from the Hot Plate Assay                                       Compound                                                                      Tested         Subcutaneous                                                   ______________________________________                                        Example No. 47 2.4                                                            ______________________________________                                    

Example 62 Opiate Binding Assay

The Jacobson Compound and compounds within the present invention werealso evaluated in an opioid radioligand binding assay, which measuresthe affinity of opioids for specific opioid receptors in rat forebrain,by their ability to displace the binding of radiolabeled ligandsspecifically bound to μ and/or δ opioid receptors isolated from ratbrain. Compounds which are determined to be active in this in vitroassay will generally have opioid-like effects in animals, includinganalgesia, unless they are not bioavailable.

A purified homogenate of receptor membranes was prepared from the brainsof the rats according to the method described by K. J. Chang et al.,"Multiple Opiate Receptors: Enkephalins and Morphine Bind to Receptorsof Different Specitivity," J. Biol. Chem., 254, 2610-2618 (1979).

Male Charles River Sprague-Dawley albino rats weighing 150 to 300 g werestunned and decapitated. Their forebrains (minus the cerebellum andassociated hindbrain) were quickly removed and rinsed in ice-cold 50 mMTris buffer, pH 7.4, and homogenized in 20 volumes of buffer with aPolytron (Brinkman) at setting 6 for 30 seconds. The membranes werewashed by centrifugation for 20 minutes at 30,000×g, followed byresuspension to twice the original volume. The homogenate was incubatedat 25° for 1 hour, followed by centrifugation as above.

The resulting homogenate was then assayed for protein content accordingto the method described by Itzhaki et al., "A Micro-Biuret Method forEstimating Proteins," Anal. Biochem., 9, 401-410 (1964). The finalpellet was resuspended to a protein concentration of 10 mg protein permL (assuming 6% of wet weight is protein) and 4 mL aliquots were rapidlyfrozen in liquid N₂.

The binding of compounds to the rat brain opiate receptor membranepreparation containing either δ or μ opioid receptors was measured usinga modification of the method of C. B. Pert et al., "Properties ofOpiate-Receptor Binding in Rat Brain," Proc. Natl. Acad. Sci., 70,2243-2247 (1972).

The opiate binding assays were conducted in triplicate at 37° C. in 50mM Tris/HCl buffer at pH 7.4 in a final volume of 1 mL, using varyingconcentrations of the compound being evaluated. Each of three tubescontained 0.8 mL of homogenate containing approximately 1 mg/mL ofprotein. ³ [H]-DAMPGO (2.0 nM) and ³ [H]-DSLET (1.0 nM) were used tolabel the μ and δ opiate rat brain receptors, respectively.

The "percent displacement" of radiolabeled ligand (³ [H]-DAMPGO for theμ receptors and ³ [H]-DSLET for the δ receptors) bound to the μ or δopioid receptors by a compound was determined at differentconcentrations of the compound (10 μM, 1 μM, 100 nM and/or 1 nM).Because the radiolabeled ligand and the compound compete with each otherfor the opiate receptor binding sites, the greater the percent ofdisplacement of the bound radiolabeled ligand, the better the compoundis in terms of its ability to bind to the opiate receptors and, thus,the more potent is the compound. "Specific binding" of a compound of thepresent invention to the μ or the δ opiate rat brain receptors wasdefined as the difference between total binding and that in the presenceof 10 μM of levorphanol.

For those compounds which bound particularly well to the opiatereceptors, the mean IC₅₀ value (that concentration of a particularcompound which is required to have 50 per cent of the bound radiolabeledligand displaced from the opiate receptors) was calculated (nM). IC₅₀values were determined from log-logit plots of concentration vs. timeresponse curves. Comparison of IC₅₀ values in this assay system providesa measure of the receptor selectivity of the tested compounds.

Finally, for those compounds for which a mean IC₅₀ value was calculatedfor both the μ and δ opioid receptors, the ratio of the mean IC₅₀ valuesfor the μ and δ opioid receptors was determined. This ratio indicateshow selective a particular compound is for the δ opioid receptors. Thus,if the ratio of the mean IC₅₀ values is 1.0, the compound isapproximately equally selective for both the μ and the δ opioidreceptors. The greater the number is above 1.0, the more specific thecompound is for the δ opioid receptors. The smaller the number is below1.0, the more specific the compound is for the μ opioid receptors.

The results obtained from this opiate binding assay are shown in TableIV below, and correspond to the compound shown and described in theparticular example identified below which corresponds thereto. As TableIV shows, compounds within the invention have a good affinity for boththe μ and the δ opioid receptors and, thus, would be predicted on thisbasis to have analgesic activity.

                  TABLE IV                                                        ______________________________________                                        Data Obtained from the Opiate Binding Assay                                   Example           Mean IC.sub.50                                                                          Mean IC.sub.50                                    Number            Value     μ/δ Ratio                                ______________________________________                                        Jacobson Compound (μ)                                                                        0.6       0.3                                               Jacobson Compound (δ)                                                                     2.0       0.3                                               Example 47 (μ) 0.4       1.3                                               Example 47 (δ)                                                                            0.3       1.3                                               Example 51 (μ) NC        NC                                                Example 51 (δ)                                                                            >50       NC                                                Example 52 (μ) 0.6       0.2                                               Example 52 (δ)                                                                            32        0.02                                              Example 48 (μ) 0.3       0.1                                               Example 48 (δ)                                                                            2.9       0.1                                               Example 22 (μ) 2.6       0.8                                               Example 22 (δ)                                                                            3.1       0.8                                               Example 10 (μ) 3.3       0.8                                               Example 10 (δ)                                                                            4.0       0.8                                               Example 23 (μ) 1000      10                                                Example 23 (δ)                                                                            100       10                                                Example 11 (μ) 1000      10                                                Example 11 (δ)                                                                            100       10                                                Example 12 (μ) 3.4       0.1                                               Example 12 (δ)                                                                            31.4      0.1                                               Example 54 (μ) 3.3       0.04                                              Example 54 (δ)                                                                            88.8      0.04                                              Example 24 (μ) 3.7       0.01                                              Example 24 (δ)                                                                            562.2     0.01                                              Example 4 (μ)  1000      10                                                Example 4 (δ)                                                                             100       10                                                Example 16 (μ) 0.51      0.7                                               Example 16 (δ)                                                                            0.78      0.7                                               Example 14 (μ) 0.54      0.8                                               Example 14 (δ)                                                                            0.64      0.8                                               Example 57 (μ) NC        NC                                                Example 57 (δ)                                                                            100       NC                                                Example 18 (μ) 0.33      0.07                                              Example 18 (δ)                                                                            4.7       0.07                                              Example 20 (μ) 1.2       0.06                                              Example 20 (δ)                                                                            19.3      0.06                                              Example 26 (μ) 19        0.6                                               Example 26 (δ)                                                                            29.8      0.6                                               Example 8 (μ)  <10       NC                                                Example 8 (δ)                                                                             28        NC                                                Example 33 (μ) <10       NC                                                Example 33 (δ)                                                                            ˜2  NC                                                Example 30 (μ) <10       NC                                                Example 30 (δ)                                                                            100       NC                                                Example 35 (μ) <10       NC                                                Example 35 (δ)                                                                            ˜2  NC                                                Example 31 (μ) 100       NC                                                Example 31 (δ)                                                                            >100      NC                                                Example 28 (μ) <10       NC                                                Example 28 (δ)                                                                            ˜2  NC                                                Example 37 (μ) <10       NC                                                Example 37 (δ)                                                                            ˜2  NC                                                Example 39 (μ) 4.7       0.6                                               Example 39 (δ)                                                                            7.8       0.6                                               Example 41 (μ) 122       0.5                                               Example 41 (δ)                                                                            257       0.5                                               Example 6 (μ)  1.1       0.6                                               Example 6 (δ)                                                                             1.8       0.6                                               Example 46 (μ) 0.88      0.2                                               Example 46 (δ)                                                                            4.2       0.2                                               Example 59 (μ) 3.2       0.4                                               Example 59 (δ)                                                                            7.3       0.4                                               Example 56 (μ) 85.5      1.7                                               Example 56 (δ)                                                                            50.3      1.7                                               ______________________________________                                         NC = Not Calculated                                                      

The foregoing examples are provided to enable one of ordinary skill inthe art to practice the present invention. These examples are merelyillustrative, however, and should not be read as limiting the scope ofthe invention as it is claimed in the appended claims.

While the invention has been described and illustrated with reference tocertain prepared embodiments thereof, those skilled in the art willappreciate that various changes, modifications and substitutions can bemade therein without departing from the spirit and scope of theinvention. For example, effective dosages other than the preferred rangeas set forth hereinabove may be applicable as a consequence ofvariations in the responsiveness of the animal being treated to induceanalgesia, dosage-related adverse effects, if any, and analogousconsiderations. Likewise, the specific pharmacological responsesobserved may vary according to, and depending upon, the particularactive compound selected, or whether there are present certainpharmaceutical carriers, as well as the type of formulation and mode ofadministration employed, and such expected variations or differences inthe results are contemplated in accordance with the objects andpractices of the present invention. It is intended, therefore, that theinvention be limited only by the scope of the claims which follow, andthat such claims be interpreted as broadly as is reasonable.

What is claimed is:
 1. A compound having the structure: ##STR82## andthe pharmaceutically-acceptable salts thereof, wherein: R¹ is hydrogen,alkyl having from 1 to 4 carbon atoms or acetyl;R², R³, R⁴, R⁵, R⁶, R⁸,R⁹, R¹⁰, R¹¹, R¹², R¹³, R¹⁴,R¹⁵ and Y may each be the same or different,and are each independently hydrogen or alkyl having from 1 to 4 carbonatoms; R⁷ is hydrogen or t-butyloxycarbonyl; R¹⁶ is hydrogen, acetyl,##STR83## R¹⁷ is alkyl, alkaryl, alkenyl, alkylcarboalkoxy orsulfonylaryl; X is hydrogen, halogen or alkyl having from 1 to 4 carbonatoms; W is --CH₂ --, oxygen or --NH--; i is an integer of from 0 to 2;m is an integer of from 0 to 6; and n is an integer of from 0 to 6,withthe proviso that when R¹ is hydrogen or alkyl: (1) R² and R⁵ are eachalkyl having from one to four carbon atoms; and/or (2) X and Y are eachalkyl having from one to four carbon atoms.
 2. A compound of claim 1wherein R¹ is hydrogen or acetyl.
 3. A compound of claim 2 wherein R² ishydrogen or methyl.
 4. A compound of claim 3 wherein R³ is hydrogen ormethyl.
 5. A compound of claim 4 wherein R⁴ is hydrogen.
 6. A compoundof claim 5 wherein R⁵ is hydrogen or methyl.
 7. A compound of claim 6wherein R⁶ is hydrogen.
 8. A compound of claim 7 wherein R¹⁴ ishydrogen.
 9. A compound of claim 8 wherein R¹⁵ is hydrogen.
 10. Acompound of claim 9 wherein R¹⁶ is hydrogen or acetyl.
 11. A compound ofclaim 10 wherein Y is hydrogen or methyl.
 12. A compound of claim 11wherein X is hydrogen, methyl or halogen.
 13. A compound of claim 1wherein at least one of R², R³, R⁴ and R⁵ is alkyl.
 14. A compound ofclaim 13 wherein at least one of R², R³, R⁴ and R⁵ is methyl.
 15. Acompound of claim 12 wherein m is 0, 1 or
 2. 16. A compound of claim 15wherein n is 0, 1 or
 2. 17. A compound of claim 1 wherein the compoundis:Phenylmethyl[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]-carbamate, monohydrochloride;1,1-Dimethylethyl[1S-[[(2-amino-1,1-dimethylethyl)amino]carbonyl]-2-(4-hydroxy-2,6-dimethylphenyl)ethyl]carbamate;1,1-Dimethylethyl[2-[(2-amino-2-methylpropyl)amino]-1S-[(4-hydroxy-2,6-dimethylphenyl)methyl]-2-oxoethyl]-carbamate;αS-(Acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]-4-fluorobenzenepropanamide,monohydrochloride;Phenylmethyl[1S-[[[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-methylpropyl]amino]-carbonyl]-2-(4-fluorophenyl)ethyl]carbamate,monohydrochloride;Phenylmethyl[1S-[[[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]amino]carbonyl]-2-phenylethyl]carbamate,monohydrochloride; 1.1-Dimethylethyl[1S-[[[2-[(2S-amino-1-oxo-3-phenylpropyl)amino]-2-methylpropyl]amino]carbonyl]-2-(4-hydroxy-2,6-dimethylphenyl)ethyl]carbamate,acetic acidsalt;αS-amino-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]benzenepropanamide, dihydrochloride;αS-Amino-N-[1,1-dimethyl-2-[[1-oxo-3-phenyl-2S-[[trifluoroacetyl-amino]propyl]amino]ethyl]-4-hydroxy-2,6-dimethylbenzenepropanamide,hydrochloride;αS-(acetylamino)-N-[2-[[3-[4-(acetyloxy)-2,6-dimethylphenyl]-2S-amino-l-oxopropyl]amino]-2-methylpropyl]benzenepropanamide,hydrochloride;αS-(acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]-benzenebutanamide,hydrochloride;N-[2-[[2S-(acetylamino)-2-phenylacetyl]amino]-1,1-dimethylethyl]-αS-amino-4-hydroxy-2,6-dimethylbenzenepropanamide,hydrochloride;Phenylmethyl[1S-[[(2-[[2S-amino-3-[4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]ethylaminocarbonyl-2-phenylethylcarbamate,monohydrochloride; 1.1-dimethylethyl[1S-[[[2-[(2S-amino-1-oxo-3-phenylpropyl)amino]ethyl]amino]carbonyl]-2-(4-hydroxy-2,6-dimethylphenyl)ethyl]carbamate,acetate(salt);αS-amino-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]ethyl]-benzenepropanamide,dihydrochloride;Phenylmethyl[1S-[[[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-1,1-dimethylethyl]amino]carbonyl]-2-phenylethyl]carbamate,monohydrochloride;αS-amino-N-[1,1-dimethyl-2-[[l-oxo-3-phenyl-2S-[[(2-propenylamino)carbonyl]amino]propyl]amino]ethyl]-4-hydroxy-2,6-dimethylbenzenepropanamide,monohydrochloride;Phenylmethyl[1S-[[[2-[[2S-amino-3-(4-hydroxy-2,3,6-trimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]amino]carbonyl]-2-phenylethyl]carbamate,hydrochloride;Phenylmethyl[1S-[[[2-[[2R-amino-3-(4-hydroxy-2,3,6-trimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]amino]carbonyl]-2-phenylethyl]carbamate,hydrochloride;αS-amino-N-[1,1-dimethyl-2-[[1-oxo-3-phenyl-2S-[[[(phenylmethyl)amino]carbonyl]amino]propyl]amino]ethyl]-4-hydroxy-2,6-dimethylbenzenepropanamide,hydrochloride;αS-amino-N-[1,1-dimethyl-2-[[1-oxo-3-phenyl-2S-[[[(phenylmethyl)amino]carbonyl]amino]propyl]amino]ethyl]-4-hydroxy-2,6-dimethylbenzenepropanamide,hydrochloride;αS-amino-N-[1,1-dimethyl-2-[[2S-[[(methylamino)carbonyl]amino]-1-oxo-3-phenylpropyl]amino]ethyl]-4-hydroxy-2,6-dimethylbenzenepropanamide,monohydrochloride;αS-(Acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-1,1-dimethylethyl]benzenepropanamide,monohydrochloride;αS-(acetylamino)-N-[2-[[2R-amino-3-(4-hydroxy-2,3,6-trimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]benzenepropanamide,monohydrochloride;Phenylmethyl[1S-[[[2R-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]propyl]amino]-carbonyl]-2-phenylethyl]carbamate,hydrochloride;αS-(Acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]benzenepropanamide,monohydrochloride;αS-(Acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]ethyl]benzenepropanamide,hydrochloride;αS-(Acetylamino)-N-[2-[[2S-amino-3-(4-hydroxyphenyl)-1-oxopropyl]amino]ethyl]-2,6-dimethylbenzenepropanamide,hydrochloride;αS-(Acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]ethyl]-2,6-dimethylbenzenepropanamide,hydrochloride; orS-amino-N-[1,1-dimethyl-2-[[1-oxo-3-phenyl-2S-[[[(phenylsulfonyl)amino]carbonyl]amino]propyl]amino]ethyl]-4-hydroxy-2,6-dimethylbenzenepropanemide,monohydrochloride.
 18. A compound of claim 17 wherein the compoundis:Phenylmethyl[1S-[[[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]amino]carbonyl]-2-phenylethyl]carbamate,monohydrochloride;αS-(acetylamino)-N-[2-[[3-[4-(acetyloxy)-2,6-dimethylphenyl]-2S-amino-1-oxopropyl]amino]-2-methylpropyl]benzenepropanamide,hydrochloride;αS-(acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]benzenebutanamide,hydrochloride;αS-amino-N-[1,1-dimethyl-2-[[2S-[[(methylamino)carbonyl]amino]-1-oxo-3-phenylpropyl]amino]ethyl]-4-hydroxy-2,6-dimethylbenzenepropanamide,monohydrochloride;αS-(Acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]benzenepropanamide,monohydrochloride; orαS-(Acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]ethyl]-2,6-dimethylbenzenepropanamide,hydrochloride.
 19. A compound of claim 1, having the structure:##STR84##
 20. A compound of claim 1, having the structure: ##STR85## 21.A compound of claim 1, having the structure: ##STR86##
 22. A compound ofclaim 1, having the structure: ##STR87##
 23. A compound of claim 1,having the structure: ##STR88##
 24. A compound of claim 1, having thestructure: ##STR89##
 25. A pharmaceutical composition comprising apharmaceutically-acceptable carrier and a compound of claim
 1. 26. Thepharmaceutical composition of claim 25 wherein the compoundis:Phenylmethyl[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]carbamate,monohydrochloride;1,1-Dimethylethyl[1S-[[(2-amino-1,1-dimethylethyl)amino]carbonyl]-2-(4-hydroxy-2,6-dimethylphenyl)ethyl]carbamate;1,1-Dimethylethyl[2-[(2-amino-2-methylpropyl)amino]-1S-[(4-hydroxy-2,6-dimethylphenyl)methyl]-2-oxoethyl]carbamate;αS-(Acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]-4-fluorobenzenepropanamide,monohydrochloride;Phenylmethyl[1S-[[[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-methylpropyl]amino]carbonyl]-2-(4-fluorophenyl)ethyl]carbamate,monohydrochloride;Phenylmethyl[1S-[[[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]amino]carbonyl]-2-phenylethyl]carbamate,monohydrochloride; 1.1-Dimethylethyl[1S-[[[2-[(2S-amino-1-oxo-3-phenylpropyl)amino]-2-methylpropyl]amino]carbonyl]-2-(4-hydroxy-2,6-dimethylphenyl)ethyl]carbamate,acetic acidsalt;αS-amino-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]benzenepropanamide,dihydrochloride;αS-Amino-N-[1,1-dimethyl-2-[[1-oxo-3-phenyl-2S-[[trifluoroacetyl-amino]propyl]amino]ethyl]-4-hydroxy-2,6-dimethylbenzenepropanamide,hydrochloride;αS-(acetylamino)-N-[2-[[3-[4-(acetyloxy)-2,6-dimethylphenyl]-2S-amino-1-oxopropyl]amino]-2-methylpropyl]benzenepropanamide,hydrochloride;αS-(acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]benzenebutanamide,hydrochloride;N-[2-[[2S-(acetylamino)-2-phenylacetyl]amino]-1,1-dimethylethyl]-αS-amino-4-hydroxy-2,6-dimethylbenzenepropanamide,hydrochloride;Phenylmethyl[1S-[[(2-[[2S-amino-3-[4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]ethylaminocarbonyl-2-phenylethylcarbamate,monohydrochloride; 1.1-dimethylethyl[1S-[[[2-[(2S-amino-1-oxo-3-phenylpropyl)amino]ethyl]amino]carbonyl]-2-(4-hydroxy-2,6-dimethylphenyl)ethyl]carbamate,acetate(salt);αS-amino-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]ethyl]benzenepropanamide,dihydrochloride;Phenylmethyl[1S-[[[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-1,1-dimethylethyl]amino]carbonyl]-2-phenylethyl]carbamate,monohydrochloride;αS-amino-N-[1,1-dimethyl-2-[[l-oxo-3-phenyl-2S-[[(2-propenylamino)carbonyl]amino]propyl]amino]ethyl]-4-hydroxy-2,6-dimethylbenzenepropanamide,monohydrochloride;Phenylmethyl[1S-[[[2-[[2S-amino-3-(4-hydroxy-2,3,6-trimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]amino]carbonyl]-2-phenylethyl]carbamate,hydrochloride;Phenylmethyl[1S-[[[2-[[2R-amino-3-(4-hydroxy-2,3,6-trimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]amino]carbonyl]-2-phenylethyl]carbamate,hydrochloride; αS-amino-N-[1,1-dimethyl-2-[[1-oxo-3-phenyl-2S-[[[(phenylmethyl)amino]carbonyl]amino]propyl]amino]ethyl]-4-hydroxy-2,6-dimethylbenzenepropanamide,hydrochloride;αS-amino-N-[1,1-dimethyl-2-[[1-oxo-3-phenyl-2S-[[[(phenylmethyl)amino]carbonyl]amino]propyl]amino]ethyl]-4-hydroxy-2,6-dimethylbenzenepropanamide,hydrochloride;αS-amino-N-[1,1-dimethyl-2-[[2S-[[(methylamino)carbonyl]amino]-1-oxo-3-phenylpropyl]amino]ethyl]-4-hydroxy-2,6-dimethylbenzenepropanamide,monohydrochloride;αS-(Acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-1,1-dimethylethyl]benzenepropanamide,monohydrochloride;αS-(acetylamino)-N-[2-[[2R-amino-3-(4-hydroxy-2,3,6-trimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]benzenepropanamide,monohydrochloride;Phenylmethyl[1S-[[[2R-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]propyl]amino]carbonyl]-2-phenylethyl]carbamate,hydrochloride;αS-(Acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]benzenepropanamide,monohydrochloride;αS-(Acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]ethyl]benzenepropanamide, hydrochloride;αS-(Acetylamino)-N-[2-[[2S=amino-3-(4-hydroxyphenyl)-1-oxopropyl]amino]ethyl]-2,6-dimethylbenzenepropanamide,hydrochloride;αS-(Acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]ethyl]-2,6-dimethylbenzenepropanamide, hydrochloride;orαS-amino-N-[1,1-dimethyl-2-[[1-oxo-3-phenyl-2S-[[[(phenylsulfonyl)amino]carbonyl]amino]propyl]amino]ethyl]-4-hydroxy-2,6-dimethylbenzenepropanamide,monohydrochloride.
 27. The pharmaceutical composition of claim 26wherein the compoundis:Phenylmethyl[1S-[[[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]amino]carbonyl]-2-phenylethyl]carbamate,monohydrochloride;αS-(acetylamino)-N-[2-[[3-[4-(acetyloxy)-2,6-dimethylphenyl]-2S-amino-1-oxopropyl]amino]-2-methylpropyl]benzenepropanamide,hydrochloride;αS-(acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]-benzenebutanamide,hydrochloride;αS-amino-N-[1,1-dimethyl-2-[[2S-[[(methylamino)carbonyl]amino]-1-oxo-3-phenylpropyl]amino]ethyl]-4-hydroxy-2,6-dimethylbenzenepropanamide,monohydrochloride;αS-(Acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]benzenepropanamide,monohydrochloride; orαS-(Acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]ethyl]-2,6-dimethylbenzenepropanamide,hydrochloride.
 28. A method for treating pain in an animal comprisingadministering to said animal a therapeutically-effective amount of acompound of claim
 1. 29. The method of claim 28 wherein the compoundis:Phenylmethyl[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]carbamate,monohydrochloride;1,1-Dimethylethyl[1S-[[(2-amino-1,1-dimethylethyl)amino]carbonyl]-2-(4-hydroxy-2,6-dimethylphenyl)ethyl]carbamate;1,1-Dimethylethyl[2-[(2-amino-2-methylpropyl)amino]-1S-[(4-hydroxy-2,6-dimethylphenyl)methyl]-2-oxoethyl]carbamate;αS-(Acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]-4-fluorobenzenepropanamide,monohydrochloride;Phenylmethyl[1S-[[[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-methylpropyl]amino]carbonyl]-2-(4-fluorophenyl)ethyl]carbamate,monohydrochloride;Phenylmethyl[1S-[[[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]-amino]carbonyl]-2-phenylethyl]carbamate,monohydrochloride; 1.1-Dimethylethyl[1S-[[[2-[(2S-amino-1-oxo-3-phenylpropyl)amino]-2-methylpropyl]amino]carbonyl]-2-(4-hydroxy-2,6-dimethylphenyl)ethyl]carbamate,acetic acidsalt;αS-amino-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]benzenepropanamide,dihydrochloride;αS-Amino-N-[1,1-dimethyl-2-[[1-oxo-3-phenyl-2S-trifluoroacetyl-amino]propyl]amino]ethyl]-4-hydroxy-2,6-dimethylbenzenepropanamide,hydrochloride;αS-(acetylamino)-N-[2-[[3-[4-(acetyloxy)-2,6-dimethylphenyl]-2S-amino-1-oxopropyl]amino]-2-methylpropyl]benzenepropanamide,hydrochloride;αS-(acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]benzenebutanamide,hydrochloride;N-[2-[[2S-(acetylamino)-2-phenylacetyl]amino]-1,1-dimethylethyl]-αS-amino-4-hydroxy-2,6-dimethylbenzenepropanamide,hydrochloride;Phenylmethyl[1S-[[(2-[[2S-amino-3-[4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]ethylaminocarbonyl-2-phenylethylcarbamate,monohydrochloride; 1.1-dimethylethyl[1S-[[[2-[(2S-amino-1-oxo-3-phenylpropyl)amino]ethyl]amino]carbonyl]-2-(4-hydroxy-2,6-dimethylphenyl)ethyl]carbamate,acetate(salt);αS-amino-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]ethyl]benzenepropanamide,dihydrochloride;Phenylmethyl[1S-[[[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-1,1-dimethylethyl]amino]carbonyl]-2-phenylethyl]carbamate,monohydrochloride;αS-amino-N-[1,1-dimethyl-2-[[1-oxo-3-phenyl-2S-[[(2-propenylamino)carbonyl]amino]propyl]amino]ethyl]-4-hydroxy-2,6-dimethylbenzenepropanamide,monohydrochloride;Phenylmethyl[1S-[[[2-[[2S-amino-3-(4-hydroxy-2,3,6-trimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]amino]carbonyl]-2-phenylethyl]carbamate,hydrochloride;Phenylmethyl[1S-[[[2-[[2R-amino-3-(4-hydroxy-2,3,6-trimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]amino]carbonyl]-2-phenylethyl]carbamate,hydrochloride;αS-amino-N-[1,1-dimethyl-2-[[1-oxo-3-phenyl-2S-[[[(phenylmethyl)amino]carbonyl]amino]propyl]amino]ethyl]-4-hydroxy-2,6-dimethylbenzenepropanamide,hydrochloride;αS-amino-N-[1,1-dimethyl-2-[[1-oxo-3-phenyl-2S-[[[(phenylmethyl)amino]carbonyl]amino]propyl]amino]ethyl]-4-hydroxy-2,6-dimethylbenzenepropanamide,hydrochloride;αS-amino-N-[1,1-dimethyl-2-[[2S-[[(methylamino)carbonyl]amino]-1-oxo-3-phenylpropyl]amino]ethyl]-4-hydroxy-2,6-dimethylbenzenepropanamide,monohydrochloride;αS-(Acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-1,1-dimethylethyl]benzenepropanamide,monohydrochloride;αS-(acetylamino)-N-[2-[[2R-amino-3-(4-hydroxy-2,3,6-trimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]benzenepropanamide,monohydrochloride;Phenylmethyl[1S-[[[2R-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]propyl]amino]carbonyl]-2-phenylethyl]carbamate,hydrochloride;αS-(Acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]benzenepropanamide,monohydrochloride;αS-(Acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]ethyl]benzenepropanamide,hydrochloride;αS-(Acetylamino)-N-[2-[[2S-amino-3-(4-hydroxyphenyl)-1-oxopropyl]amino]ethyl]-2,6-dimethylbenzenepropanamide,hydrochloride;αS-(Acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]ethyl]-2,6-dimethylbenzenepropanamide,hydrochloride; orαS-(Acetylamino)-N-[3[[[2S-amino-3-[4-hydroxy-2,6-dimethylphenyl]-1-oxopropylamino]phenyl]benzenepropanamide,hydrochloride; orαS-amino-N-[1,1-dimethyl-2-[[l-oxo-3-phenyl-2S-[[[(phenylsulfonyl)amino]carbonyl]amino]propyl]amino]ethyl]-4-hydroxy-2,6-dimethylbenzenepropanamide,monohydrochloride.
 30. The method of claim 29 wherein the compoundis:Phenylmethyl[1S-[[[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]-amino]carbonyl]-2-phenylethyl]carbamate,monohydrochloride;αS-(acetylamino)-N-[2-[[3-[4-(acetyloxy)-2,6-dimethylphenyl]-2S-amino-l-oxopropyl]amino]-2-methylpropyl]benzenepropanamide,hydrochloride;αS-(acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]benzenebutanamide,hydrochloride;αS-amino-N-[1,1-dimethyl-2-[[2S-[[(methylamino)carbonyl]amino]-1-oxo-3-phenylpropyl]amino]ethyl]-4-hydroxy-2,6-dimethylbenzenepropanamide,monohydrochloride;αS-(Acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]-2-methylpropyl]benzenepropanamide,monohydrochloride; orαS-(Acetylamino)-N-[2-[[2S-amino-3-(4-hydroxy-2,6-dimethylphenyl)-1-oxopropyl]amino]ethyl]-2,6-dimethylbenzenepropanamide,hydrochloride.